[gearbanger]

Jim, the test would be the octane test. If you have to run supreme in your iron head combo, but your aluminum head combo didn't need that. Cliff's car ran quicker and faster with 89 than 93 with 10.5:1 compression.

I think the results of the test that you were talking about is probably because the aluminum heads had design features that improved the performance enough to offset the heat disappation effects of the aluminum. Had they raised the compression of the alum heads to have equal fuel requirements as the iron head, I feel sure that the aluminum head would have outperformed the iron heads.

In your case, your iron heads had been optimised for your combo and 93 octane fuel, so the improvements that the KRE heads have were not enough to fully offset the difference in fuel requirement. You simply needed more compression to exceed the performance of you iron heads. And that would have easily been possible with the aluminum.

[Skip Fix]

Jim I've read Vizards articles. He HAS mapped velocity and measured it. I don't think we have on Pontiac heads.few shops I've been to have a velocity manometer. I've read other experts that agree in some areas and disagree in others. His articles often are abbreviated in different magazines. The same general articles appear in different magazines with different additions or subtractions. Many others now use the CSA(cross sectional Area) instead of port volume to determine how a motor will respond.Intake runners or exhaust pipe cc are just port extensions so they add more variables that CSA. A longer dual plane runner wil make a different total cc than a shorter single plane, but shorter than a M/T crossram.In fact most experts now use that much more than port cc for intake as well as exhaust.

The Pontiac engineers did NOT loose streetability adding 30cc intake port volume. If that is the case why did these motors not loose torque and street manners? Were they wrong? I'll bet they spent alot of devlopmental time and $ testing a totally new port and chamber. Were the factory ratings wrong and really the HO/SDs had less power? They would have to using only port volume/velocity theory we are here.

Yes Lynn uses high rpm compared to your 460 motor but less that other brands in his group. That still does not refute the fact that the cylinder head experts feel too much velocity is bad in whatever rpm range you run for the reasons he and I both mentioned.I believe even Vizard has mentioned that somewhere.

Let's ASSUME your D port motor has 50 more ft lbs at 1000-1800 than my E head motor, but at 2000 its only 10 more, at 2500 I'm 10 above and climbs greater diffeence from there. How much driving/acceleration is in the 1000 to 2000 range? How fast does the motor acelerate through that range? Is the Kaase motor with its huge ports and 100ftlbs over both of our motors at 2500 going to be a no streetable? Maybe because it roasts the hides too easily.

You are also leaving exhaust ports totally out of the equation. Most experts do NOT,including Vizard! It is an average of intake CSA rpm range and exhaust CSA rpm range that determines where the motor likes. What were the CSAs on the intake ports, exhaust ports, exhaust port ccs? All of those also are a big factor.

You still miss my point, there were many other things in your test besides the intake port size that could have affected performance that may or may not affect other motors performance in a similar manner.

Are you stating that port shape, chamber shape do not affect mixture filling in the cylinder but only size does?