A revolutionary, fast and hyper accurate way of spec’ing and selecting catalog cams; A system that finally eliminates the fog of cam selection.
The revolutionary (and I seriously mean revolutionary) cam spec’ing technique that I am about to show you is at least 12 years late in arriving at the desks of pro and pro class enthusiast engine builders desks. All because somebody said “we have some clever guys working for us you know”.
Here in simple terms is what it delivers:
Speed Selection – 15 second cam selection.
Speed Timing – dramatically more precise valve events.
“Speed Spec” for catalog cams did not suddenly materialize out of near thin air. In essence it is a simplified high speed, paper friendly offspring of my immensely functional ‘Cam Master’ program. To better appreciate how “Speed Spec” came into being I need to fill you in on the genesis of ‘Cam Master’.
Cam Master Genesis
Cam Master is a computer program that very accurately determines what an engine needs in the way of valve events (opening and closing points) for optimal results from the particular spec of engine concerned as opposed to a generically similar one. It has its roots far back – in fact over three decades before a fully operational Alfa program was up and running.
Way back when I was a new student to the science of engine development (late 1950’s) I wondered why engines would have differing optimal valve event timing. What, I asked myself, were the factors involved. Well back in those days I had much else to concern me as far as my education on developing engine performance was concerned. I had already built a crude but effective flow bench which was teaching me heaps of go-fast tech in terms of cylinder head mods. It was not until successful and nationally recognized UK engine builder Harry Ratcliffe of BVRT happened to mention to me that he had noticed that the short stroke big bore Ford 105E range of engines generally like to have the Lobe Centerline Angle at 109 degrees where as the long stroke ‘A’ series engines that powered the Mini Coopers of the day were more disposed to 104 or so. This comment from Harry was actually what got me started on my quest to find out what factors affected the optimal opening and closing points any particular spec of engine needed for the strongest power curve in the desired rpm range.
All the forgoing was back somewhere in the mid 1960’s. Over the next 30 years my involvement in the cam aspect of engine development became ever deeper and more involved. In 1971 I began, as an outside consultant, working with the UK division of Chrysler, or more accurately their competition department. That year they introduced the then new-from-the-ground-up Avenger. Loosely my job description here was to popularize it as a performance vehicle. That was all very well but there was almost no speed equipment in existence for this engine and certainly close to zero know-how on what was needed to make it perform. I went to work investigating this somewhat unorthodox engine and making modifications accordingly. My efforts here rapidly outpaced the factory’s. They must have liked my efforts because the first simple projects lead to more ambitious ones. Eventually I was developing an ultra wide power band version of the production line Avenger engine and a turbo version of such to put Ford’s Lotus Cortina twin cam in it’s place (i.e. behind an Avenger). As it happened I pulled off both projects with apparently great success. Motor Magazine tested my ultra wide power band Avenger (useable power from 400 rpm to 8000 and I am still waiting for a VVT engine to match
that). Even at 1500 cc it whooped the butt off the newly introduced 1600 Cosworth BDA Escort in every respect. The differences were far from marginal, and, as the magazine’s road test editors put it, embarrassing for Cosworth. As for the Turbo Avenger this project went very well producing an emission legal 0-100 mph in 13 seconds. Since, at that time (1972), I had zero experience with turbo motors I thought I would seek some guidance before starting this project. This, for you older folk, was the era when the Turbo Offy’s made their mark in Indy Car racing. One of the prime movers in this respect was Ak Miller. So in January of ’72 I left the freezing whiles of England’s Cotswold hills and headed to the summer-like climes of LA California where I met up with Ak Miller. I have only met up with Ak once since then but he made a lasting impression on me. I am sure had he not been such a great engine and in particular turbo guru he could have made a really outstanding living as a comedian. Ak was a very likable and dynamic character. The info he so freely gave me in 8 hours (along with breakfast, lunch and dinner) on the ins and outs of turbo motors was to stand me in excellent stead in my quest to build a world class turbo Avenger.
With Chryslers Competition Dept., supplying whatever I asked for I found I was in the best position to-date to do some experimentation with cams. I had learned a lot from building race winning Mini and Ford engines in the dozen or so years to this point and built on that. Cam experimentation went on for both the wide power band engine as well as the turbo project. For the wide power band engine I got considerable help from Chrysler’s chief engineer John Clarke. I have to tell you my working life has been one that has caused me to be surrounded with remarkably clever people. Not just one or two but dozens. John Clarke was one of these individuals. With his usual white coat and reading glasses he had ‘scientist’ written all over him and looked every bit like he was about to play the part of a scientist in a Disney movie. Some years before my meeting with John I had had a long conversation with Harvey Crane (the first of what turned out to be many and a subsequent close and life long association with the cam miester) who had graciously given me a lot of his time to explain what some of the valve train issues I was seeing on my 10,000 rpm mini engines might have been. As you may have supposed Harvey was of great help and what I learned from him put me in good stead to take the next step and learn from John Clarke’s mathematical world in a meaningful manner. It was working with John that I saw my first super high speed film of a valve train running through a working rev range and played back at about a thousandth of the speed. I could hardly believe what I saw but that’s a story for another day.
All the forgoing with Avenger engines gave me an additional window into the workings and requirements of an engine very different to the Ford and ‘A’ Series engines I had worked with to date. It also allowed me to make a direct comparison between the requirements of a normally aspirated engine versus a turbo one. By the time my year as a driver/car constructor in the British Touring Car Championship came up I had, though still far from mathematically quantified, a good handle on what any particular engine needed for maximum performance. This proved itself out in a very public way. In spite of being a privateer against a field of factory entered cars my BTCC 1600 Avenger Tiger was the fastest by far in the class even though it was (other than the factory entered Avengers) the only pushrod, all iron, motor competing. In six of the races I broke a motor in during practice forcing me to start way back as far as 28th on a 32 car grid. On each occasion I was up to first or second in class by the end of the first lap. The most dramatic of these through-the-field charges was at Brands Hatch where the BTCC event was the main supporting race of the British Grand Prix and was televised. Again breaking in a motor put me on the last row but one. If ever there were doubters to the possibility that I may have an inkling on how to make hp this should have been a convincer that I could – and one of major proportions at that. From my 27th starting spot I took my 1600 cc racer to joint first between two 350 Z28 Cameros – by the first corner! Yes you read right – I passed 24 cars in the time it took for the start lights to turn green and my arrival at turn #1 (Paddock bend). As for witnesses – well several million TV viewers saw this happen. As you might expect I am by this time starting to actually justify the nickname of Vizard-the-Wizard or Mr. Horsepower.
The stunt at Brands though was hardly the first time I had pulled off something like this. A couple of years previous, I had, on a damp track at Prescott and in my 1293 cc Mini Cooper, beaten all the times of the F1 cars. The only single seater to beat me was a four wheel drive Formula 5000 car which bettered me on a drying track to the tune of a scant nine thousandths of a second! (that 1293 had one of my cams in it as well as a DV ported head and a bunch of other stuff I made because I could not afford to buy it.)
All through the 1970’s I built on my successes in the cam and head departments of high performance engines. By the time the 1980’s rolled around I am seeing work come in from notable cam companies. I get cam testing assignments from the likes of Iskenderian (known Ed Iskenderian since 1972 and he still refers to me as ‘Young Vizard), Crane, Comp Cams and the like in the US and Piper and Kent in the UK. At first the cams being tested were only in ones and twos to maybe a dozen or so. The reason, as I was told, that these cam companies came to me or were very willing to work with me is because my dyno testing was meticulous to a point.
In the early 80’s I did a cam makeover project for Piper cams in the UK. The results were dramatic both in terms of improved performance and sales. To quote Pipers boss ‘the results were beyond our wildest dreams!’
About 3 years on from the Piper deal I wrote an article in Cars & Car Conversions (a magazine I used to write for regularly until some conflicts with editors and staff who unthinkingly put me in a position of making things even harder to generate new and exciting material) that stated, in big bold wording, that I thought it a poor deal that neither the factory (British Leyland) nor England and Europe’s leading cam grinders actually knew what they were doing when it came to cams for the ‘A’ series engine (which at that time was the most popular engine to hop up by a country mile). Wow – think about that – here is a mere motoring journalist (I am actually an engineer not a journalist but whatever) is saying – in a very public forum and using my own name, not hiding behind the anonymity of some pseudo name, and saying the factory, and virtually all others, do not know what they are doing to a sufficient degree to be anywhere near optimum for the duration figures involved. I don’t suppose for one second that you will have a hard time believing that this stirred up a hornet nest.
When questioned by potential customers and the press the guy at British Leyland just blew it off by saying that as a journalist I need to write something sensational and that I would not – and probably could not back up such an obviously outlandish claim. The reality was that I was tired of being polite as it got me no where. I was getting ticked off by BL’s Competition Departments near lack of any apparent capability to advance the state of art and the very thing I wanted them to do was to take me up on it so I could show them what they were missing out on. I had commented several times to the guy that made the dumb press statement that I would love to go through their cams and update them from the Stone Age to something at least a couple years in advance of the then current state of art. He just blew off any suggestion that they wanted, or even needed, to update anything especially with the aid of a journalist! Back then BL’s race profiles dated to pre 1958 era. What a bunch of go getters they were!
The comments from BL’s staff did not really hold any great surprises but I was rather surprise of the cool reception my magazine comments had from Piper as I had already proved what I could do with only a minor budget to work with. On the other hand Kent cams Bob Munt called me up and said “let’s see if you can put your money where your mouth is”. So we struck a deal. Bob was to find the most successful ‘A’ series engine builder in the country and ship him and a selection of representative dyno mules over to my shop in Riverside California. There I was to show just how much better my cams were than whatever was currently being used. The engine builder Bob Munt chose was an extremely successful ‘A’ Series engine builder that had, that year, (and several previous and subsequent years) virtually cleaned up in any class where a Mini was eligible. I seem to remember that out of four championships this guys engines took the first four spots on three of them and the first three in the remaining championship. This highly successful engine builder was the now famous (in European circles) Dave Mountain of Mountune Racing in Malden just east of London, England. Dave was also one of my protege’s. If I ever needed to offer proof that I can teach not just race but championship winning engine building technology then Dave will, I’m sure, bear witness to such.
So after a few months had gone by Dave Mountain arrived in Riverside California along with 4 test engines ranging from 1000 to 1480 cc. Dave was, as you might expect, a dyno hound. It took him almost no time flat to have his big championship winning spec 1480 on the dyno and up and running.
The events that transpired next I remember like they were yesterday. After making a fully dialed in pull Dave said, as he smilingly handed me a dyno printout, “well boss what do you think of that?”. It was very much a see-how-good-this-is deal. I looked at the numbers and said “not bad for a youngster!”. I followed this up with “go get the cam in the white box, third from the left on the second shelf over there. It’s one of my hot street cams” Dave’s response: “that motor has a race cam in it now – how big is this street cam?”. My answer “12 degrees shorter than the one you have but it opens and closes the valves at points the engine wants not what the engine builder thinks it should have.” I stood by and watched Dave change cams. He did this in an almost unbelievable 27 minutes from the moment he laid hands on the hot engine until it was re-fired. A couple of pulls for timing optimization and a mixture check showed my hot street cam to be 8 lbs-ft and 12 hp up on the race cam it replaced. Also the engine would pull from almost a thousand rpm lower to about 500 more at the top end. (Not bad for a journalist the factory would barely give the time of day too eh?)
At this point Dave Mountain asked if he could call Bob Munt back home in the UK. I pointed out that it was 2:00 am back in the UK. Dave’s answer “I know it is”. He goes ahead and calls Bob at home and when Bob answers Dave say’s (and this is verbatim) “Bob, Dave Mountain here – you owe me one thousand pounds” (about $1800 bucks at that time). Dave then hung up. You can see the inference here. Bob had just lost a sizable wager by betting I could not live up to my claims (tut tut). That was the down side but I doubt he was even minutely bothered by loosing such a big bet. Why? Because the fact I had made such a huge improvement meant that he was likely to sell a substantial fortune’s worth of superior cams. During the 6 weeks or so I worked with Dave Mountain and with the valuable assistance of my good friend David Anton (of Advanced Performance Technology in Riverside CA) I developed a range of conventional cams for the ‘A’ Series that simply out powered anything out there by a very substantial margin. (My eldest daughter Samantha, scored an 88% win record with her street weight 1275 Mini GT and was never beaten by anything less than 3.1 liters. No pro built mini, even at race weight, nor a factory entered mini could hold a candle to it) Cam sales at Kent went through the roof! If I remember rightly in some four months their sales about quadrupled!
When Bob Munt came to pick up the results he said, before arriving, he wanted all the results not just those I had sorted through. I told him he probably would not want them all. At this point he said “Yes I will – they cost a bunch to get and I want to be able to look through the whole lot”. Once again I said this would probably not be the case. Well Bob arrived at the shop and asked where the results were. I pointed to a stack of tractor feed printed results – a stack comprising of over 11,000 tests! Suddenly Bob did not want all the results.
That year was a year to remember in terms of cam testing. Almost right after this I got a call from Harvey Crane asking if I could do a big cam test for him. This would involve not only testing the cams but also testing them and optimizing advance and retard and the effects of low and high lift rockers on first the intake then the exhaust then both. A 350 CID small block Chevy was built for this and I had on hand a 383 and a 406 with which I could conduct further tests which at the time were outside the scope of those Harvey had asked me for. All this happened at the end of April and by the middle of October I had amassed over 8000 meaningful results from probably close to 20,000 pulls. Again I had considerable help in the wrenching department from David Anton and some of my mechanic cronies. What with a split timing cover and a split intake manifold we could swap out a flat tappet cam from shut down to re-fire in as little as twelve minutes.
The rest of the year I got a number of smaller cam test jobs but the following year I was re employed by Kent to develop the ultimate ‘A’ Series cams, cams for the MGB engine and the 2 liter Pinto engine (used in Ford UK’s Cortina and Escort RS 2000). The most novel of these cams were the Scatter Pattern cams for the ‘A’ Series. This engine, because of it’s port layout of 2 intake ports and three exhaust means that every cylinder has a different valve event requirement. The inspiration for the scatter pattern cams was once again the venerable Harry Ratcliffe who had tried this some 20 years previously. Well with the equipment of the day I was sure that Harry was really up against the odds of getting it all right-on so David Anton and I, equipped with a really up-to-the-minute dyno tackled the problem of determining how to figure the optimal events for an engine that did so much port sharing and consequently inter-cylinder robbing. We really could have done with in-cylinder pressure measuring gear but it was well beyond my budget back then. So I had to come up with another method to get to where we had to go. I won’t detail it here as I am saving it for my techno memoirs should I ever get around to writing them. The scatter pattern cams really worked out well and I believe David Anton and I progressed the state of art quite some way from where even the talented Harry Ratcliffe left off. These cams simply blew away any then available into the weeds – and nothing much appears to have changed in this quarter since.
The rest of the cams that Kent commissioned me to do also proved to be a great success. I did the MGB cams in close association with David Anton here as he was about as good as it gets when it came to building MGB engines. There’s another guy that BL’s Competition Department should have been paying big bucks to instead of whomever they had at the time. Back then David was building totally street drivable ‘B’ with more torque and HP than the factories competition engines were making.
I think I have made the point that I have plenty of R&D experience in the cam department but let me finish by saying that between 1982 and 1989 I delivered, to various clients some 19,200 sheets of results of successful cam tests. That does not include the unsuccessful ones which incidentally, I also learned a lot from.
So what was the motivation for all this cam work. Well there was several in fact. The first is I don’t like to tackle any job and be second best at it. Virtually everything I do is done with the intent of being the best there is at that moment in time. I’m sure that now I have made the point any of you that have my books see this is evident. I need to show my readers, at the time of publication and into the foreseeable future, how to build the very best engines within any given group/brand/application not the second best. That means doing my own R&D and doing it to absolutely the best of my ability. Also I did not see the cam companies doing their own research to any great degree when it came to the subject of what events an engine actually wants for optimal output. The fact I deliver performance engine tech that not only works just as I say it will but also can be applied, for the most part, by any serious performance enthusiast means my engines have to be as good or better than the pro’s are currently building.
These ‘it works just like I said’ tech articles (and books) has lead to an overwhelming demand for my performance how-to articles. During one crazy period of almost two years I was writing no less than 18 articles a month for twelve different magazines. All the material for such was coming from engines I built and tested not some third parties. I think the biggest time crunch was just before I was due to leave the UK for my ‘Round America Economy Drive’ in a 50 mpg at normal cruise speeds mini that a team of 5 engineers (of which I was the lead one) had developed. This would take three months and three or four of the mags I was writing for got in a minor panic thinking that they would have no DV features on hand. To avoid this they ordered enough to keep them going during my absence. In the 11 days prior to my leaving for New York I wrote 11 main features. These I dictated to my secretary. Time here was absolutely pressing – I was even dictating to her while I was in the bath (there was plenty of bubbles so no embarrassing moments)
Through the early 90’s I continued cam work and utilizing my expertise in this area with various magazine project engines. Whatever brand of cam I used it was never an off-the-shelf deal but always one I specced out. I really needed to maintain the quality of the builds I was doing (no second rate stuff) and I did not have time to flush cams through an engine just because the cam companies where unable to accurately pin point what was needed. Well, I was not about to wait for the cam companies to come around in this quarter so I decided I would have to do it myself. Heck I could always present it to one or other of the big companies after I had done the bulk of the work (that seemed very logical but things subsequently did not work out that way). During the early 90’s Cam Master was conceived and began to take shape in the form of mathematical modules that predicted one particular aspect of cam and engine geometry interaction. The formulas developed were from observed results not first principles. A formula like this is known as an empirical formula. You start with the results and develop a formula to fit. Doing things this way to a competent degree means formulas that fit the real world not the theoretical world. I bring this up because I have had people say that Cam Master is only a paper theory. In reality they could not be further from the truth. Cam Master is a ‘reality based’ program and is more than likely the only cam prediction program out there that is so.
After dedicating some nine months to the job the first workable program saw the light of day in late ’97 and was put into the field for testing by my close friend Denny Wycoff (now retired) of Motor Machine and Supply in Tucson Arizona. It was an instant success. I would hazard a guess that we set more track records and scored more wins per cam sold than any cam company on the face of the planet! We found that the greatest section of return customers for a cam spec was the top of the line professionals who stayed in business by winning races and championships. The reason they came back for us to spec subsequent cams was because the dyno told them they should.
In ’98 after presenting a one hour seminar at the Advanced Engine Technology Conference (AETC) on valve seat design and it’s less than fully appreciated importance I showed Cam Master to one of the cam industries principle players. I thought he would be really interested in a program that would allow his company to say, with all honesty, (as opposed to PR bragging rights which are always a bunch of baloney) that their cams, for any given duration and lift, could not be beaten for output only equalled and then more by luck than judgement. I was amazed that this gentleman, after watching the demo, just looked at me and said (quote) “we have some clever guys working for us you know”. At which point he walked off and left me totally stunned by his answer. I had grown to expect an answer like that from British Leyland’s Competition department but from a well known cam company that prided themselves on advancing the state of art? No – I was bewildered to say the least. Still I did not have too much time to worry about this because, on my return to California, I was hired by a company to work on super advanced F1 piston and valve train stuff that I cannot talk of even now as it is still under-the-radar technology. I even had to build a super accurate dyno to do the tests for this and, what with one thing or another, this project consumed me for almost two years. At the end of the project I was so worn out with 100 hour plus weeks that I took myself and family to the paradise island of Tobago (and it truly is) in the Caribbean for a year. Here I spent most of my time in the gym, on the beach, running, or driving drag and road race cars in Trinidad. On returning to the US I took up writing articles again and built, or helped on, a number of race winning and high output street motors for various magazines and clients. In each case I used Cam Master to determine what cam the engine needed. On several editorial occasions the cam company asked me to use an off-the-shelf cam which I did at least try. But I also bought one that was to my spec. On every occasion I did this my numbers were typically 20 hp and twenty or so lbs-ft up on the off the shelf cam sent to me. Telling my readers how to build a motor 20 numbers down on what they could have is just not my style. As a result I used the curves from my cam not the off-the-shelf cams otherwise supplied. Of course the cam company still got credit for supplying the cam so I did not get too much flack from them on this score.
About 2006 I was asked by one of my publishers (Cartec) to update my top selling book ‘How to Build Max Performance Small Block Chevy’s on a Budget’. It was about time. The original book was in black and white and color printing was now the norm. Also there had been a performance hardware revolution that made for an entirely new approach to the job of building a small block Chevy on a budget. The new book was to be virtually a total re-write.
The new manuscript involved the building of about a half dozen dyno mules to illustrate various aspects of making power. When it came to the cam section I realized that some 8 years had gone by and the clever guys at the un-named cam company were not even close to solving the event problem. What I needed, to bring my books cam selection section into the 21 century, was a simplified but still functional paper version of Cam Master. The cam companies where apparently in no position or in no hurry to bring about new and better cam selection techniques so I figured that once again I would have to do it myself. This often ticks off folks within the industry as they see a journalist’s job as one of telling the rest of the world how good they are – not someone who is leading the way with them in tow or, worse yet, nowhere to be found. My answer to that is the same one I would have given British Leyland’s Competition Department if the opportunity had arisen. That is – if you were really doing your job then I wouldn’t have to be doing it for you!
Rather than do what every other performance book to date has done (give you enough info to leave you completely mystified as to what you should use) I came up with a chart system which put a very small spec band width with a specific cam and application. To put it bluntly you could be a complete idiot and still get it right.
Normally Cam Master uses the flow figures of the cylinder head to model the engine and subsequently generate a precision cam spec for the engine. Unfortunately only a small percentage of people know what the flow figures of the various components that make up the entirety of the engine are. By substituting valve size I could reasonable closely approximate the key parameters involved and allow anyone who can read, yet have no previous knowledge of how an internal combustion engine even works, to spec a cam to better than 98% optimal. What this resulted in was a lookup chart that was by far more accurate then the fog-like method typically found in all cam catalogs. Cranes old catalog (prior to 2008) used 29 pages to dubiously describe cam specs and the possible applications. Utilizing the Cam Master derived chart method replaces those 29 pages with just 5 pages and leaves the person selecting the cam absolutely in no doubt as to what should be used for the best output.
So that all this could work just by calling up and ordering a cam without any ado it was necessary to team up with a cam company(s) that was willing to grind cams my way – not theirs. You would think my past track record here would make this real easy. It’s like I tell people inventing something is relatively easy but selling it into a society that suffers to a great extent with the not-invented-here syndrome is another thing altogether.
In my bid to sell this new approach to selection and the more powerful event timing it carried with it I first approached Crane. Why Crane? Because, at the time, they looked like they needed saving. Unfortunately the boss at the time was way too slow to make a decision and all fell through before they went belly up which in itself was, I suppose, a blessing to me (they are back now under new leadership and that promises to be a good thing but ultimately we will have to wait and see). Next I approached Comp Cams and they were reluctant to change what they were doing as they were already dominating the market. However the bosses there had just acquired Lunati cams and suggested I go with that company to get what is in essence a line of Vizard specced cam produced. So that is what I did and fortunately for me Lunati had some pretty good profiles for me to work with.
If you have the latest edition (it’s in color) of my book on max performance budget small block Chevy’s then you will find a wide cam selection specifying exactly what cam to use with what spec of engine in the last 3 pages of the cam chapter. I have done the same for my big block Chevy book which will be out about the end of May 2011.
Speed Spec Cams
Now let’s get down to specifics. These Speed Spec cams bring the cost conscious custom engine builders cam technology out of the 1970’s and well into the 21st century. The advantages of using this catalog selection method over all previous ones is 1) super rapid selection (about 15 seconds start to finish) and 2) far more optimal valve event timing by several orders of magnitude. This is not only way faster than previous catalog selection methods but also more accurate than switching on your computer and firing up a top end computer simulation program. As outlined earlier these cams are the result of literally thousands of dedicated cam and valve train dyno tests and the extremely precise computer modelling capability of my one-of-a-kind Cam Master program.
Using the catalog sheets that follow an engine builder can home in on a cam spec not just for a Chevrolet engine in general but for the precise spec of the Chevy engine that is actually being built. As time goes by I will be adding more applications (Ford and the like) utilizing not only Lunati profiles but the top performing ones of other companies. Doing so you will find, compared to a regular catalog selection, that time is cut from 15 minutes or more for a dubious result to 15 seconds for a very precise result! Not only will this save you time but in so doing you can expect, on average, to have your typical 350 inch engine produce an extra 20 lbs-ft & 20 hp with no down side!
Not unexpectedly an engine builder’s reputation hinges on the ability to produce high power and torque numbers in a reliable and cost effective manner.
Consider this – it costs no more to purchase a cam with the right valve events for the application than it does for a cam with the wrong ones!
About the Lunati/Vizard cams.
The cams shown in the following charts (currently for small and big block Chevy’s) represent a range of cams which specifically addresses the most critical and influential valve event differences between one engine build and another. The primary factor, and one that is highly influential, is the ratio of breathing capacity (or valve size) in relation to the cubes being fed. This is why a cam with optimal valve events for a 262 small block Chevy is not even close for a 406. The most critical part of this equation is the valves flow characteristics during the overlap period. This, plus the CR, dictates most of what is needed in the way of valve event timing. Unfortunately a conventional cam catalog does not even begin to address this critical situation. As a consequence most cams selected for high performance street and street/strip use are potentially giving away a sizable amount of torque output throughout the rpm range. The problem here is not that top cam companies don’t know how to do the job it’s more a case of a slow cumbersome and expensive process dyno testing in the first instance and not being able to communicate an engines probable requirements in an effective manner to a mass audience in the second instance. Think about this. I address a very large mass audience on a daily basis and I have to do it in a manner that a tenth grader will understand. Pick the wrong cam and not only does the engine fail to reach it’s true output potential but also the situation has no redeeming upside. In other words there is no increased mileage or better idle or drivability. The engine is, to put it bluntly, not up to scratch. If a cam with the wrong event timing is used just remember that is how the engine goes out the door to the customer and, worse yet, if you are a pro and do this for a living it probably has your company’s name on the valve cover! The use of the selection system shown here is that it is not only very fast but it is unique in as much as the person selecting the cam needs no prior knowledge of how an engine works let alone have any cam selection skills.
The cam and valve train recommendations seen in the accompanying charts are not the result of a ‘think tank’ session a few hours long. Regardless of how inspired that may have been it is far from reality. For just the small block Chevrolet the dyno tests were run on three engines with a number of different heads and pistons to simulate changes in flow and compression. Along with this several other possibly pertinent factors such as rod/stroke ratio, fuel octane etc were also explored. The result was that, over an extended period, over 8000 (eight thousand) combinations were tested in the Vizard dyno shop. This, and Cam Master, a Vizard authored cam prediction program that was over 18 years in the making, gives the custom performance engine builder the most accurate, catalog referenced, cam selection method on the face of the planet. Indeed it is so accurate that it’s capability equals or outstrips all but those mega-buck main frame computer predicted valve events. The only program to do a better job than these charts that would be available to a typical commercial engine builder would be Cam Master and the only copy of this is on the Vizard computer (I can be rented, at $200/hour, to run this program and that is typically more than enough time to get the job done way faster, cheaper and more accurately than dyno testing).
So what will these cam charts and cams deliver. First and most obvious is that it will eliminate the time consuming and stressful task of pondering over a conventional cam catalog and wondering if the choice you are about to make is best for the job. The reality here is that, and this may shock you, for the engine building industry in general, as much as 95% of the cams are significantly off the mark. What these cam charts do is to allow you to choose a cam in as little as 15 seconds and then get on with the work that actually pays you – i.e. building engines. Secondly it removes any concerns you may have as to whether or not the engine shop down the road may be able to make a better choice than you.
Consider this. I am read by almost a million performance enthusiasts a month worldwide. My written material, base on personal research, not word of mouth or a third party, is put to the test hundreds, if not thousands of times a day. A reputation for delivering tech that works has successfully survived a potentially incessant onslaught in a hyper critical market place for over 45 years. I am not about to pass on any tech here that I would not be prepared to stake an industry reputation second-to-none on.
If you should have any doubts here just try one of these Lunati/Vizard cams on the dyno. In a world where nothing is for sure I am about 99.9% certain your test engine will pick up a sizable chunk of power.
To run a cam selection click on the download link below. This will cost you nothing other than a few seconds but the potential performance gains are substantial.
Download Cam Profiles
Click to see the list of available Cam Profiles.
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Hi I have just recently read your book How to Build Max Performance Chevy Small Blocks On a Budget and I read this article and I can’t seem to find the cams you listed. I know the book is older so maybe that’s why. Now I am having trouble finding the right cam for a 383 stroker.
i have the 2009 edition of this book and the cam charts are just where the article says they are, at the end of the cam chapter.