Originally Posted By camastomcat
Originally Posted By polyspheric
WRT "there is no issue at all with having big heads on a small motor"

Ford made that mistake with the Boss 302, which won't pull the skin off a chocolate pudding. The cure: 351" by stroke increase.
Harley-Davidson did the same thing with the K model in 1952: a 750cc twin with 1.56" intake ports, 50% larger than needed. The cure: 900cc by stroke increase.

Missing from the "cfm" rule: "as long as the minimum air speed in the required RPM range is about 200 f/s". Adjust the minimum depending on the application (LSR can be slower than oval).
A 3" sewer pipe flows a lot of cfm, but useless on any automotive engine.


I love your calculated responses Polysheric. You don't get enough credit here. Would love to talk with you about my stuff some time.
what did you gap your points at on your two examples.haha.. I don't think they had ignition valve spring or cam technology to take advantage of the heads

Last edited by WHITEDART; 11/06/16 06:12 PM.
In the 8s N/A.with Brett miller W8's
5.07 at 133 at 2700lb