Eric's cam challenge

I'm trying to figure out how that would work ? Guessing along with flow, csa and velocity also wouldn't be factored.

If say you took a 340 with 318 heads vs X heads vs Trick Flows and ran the same/similar cams and cr with appropriate intake and exhaust systems. Could see making similar hp per cfm but the hp and rpm be vastly different from one another. Not saying your wrong just not getting how head flow (cfm/csa/velocity) don't play a major role in cam choice?


The math some assumptions. It assumes the guy doing the math understands how to build an engine.

Surprisingly the math asks for rod to stroke ratio but not head flow. Think on that for a bit.

It also weighs more on stroke than bore size.

RPM matters, so the guy doing the math has to be honest about where he wants peak torque and power.

Did you happen to buy and read Billy Godbold’s book? He covers it in there. You just have to read between the lines.

And you have to read it all. If you don’t it might not make sense.

I mean I read it the first time and was almost half way through it and I thought how will this book ever teach how to pick a cam.

The answer is it won’t. It can’t. But what it can do is teach you what to consider when choosing events. It took me until 2/3rds of the way through before it started to dawn on me.

I’ve read the book five times already and parts of it many more times and I’m still gaining from it.

Plus the Taylor books, Obert, Larew and several others I refer to on a fairly regular basis.

As I’ve said before, looking at flow (and I suppose port size and even header construction) like it’s the end of the discussion then you are missing it.

One of the books I reference almost daily is written for engine builders. Actually most of them are. Some are engineering books. Those hurt my head and require reading many times across many years. And I still learn from them.

Think it through. It will come to you. Just visualize what’s happening right before the exhaust valve opens.

On the other side of it, visualize what’s happening right before the exhaust valve closes.