Headflow formula?

[lolsteve]

Well now im not on my phone at work was able to do some proper googlin

http://ls1tech.com/forums/advanced-engin...k-rpm.html

Here is a 4-year old quote from a great head porter and engine guy, Larry Meaux:



"Peak_HP = Flow_CFM * .257 * Number_of_Cylinders

This is the estimated potential Peak HP to expect.

You multiply 87 percent (.87) times cam's theoretical max lift , round off to nearest .050" in Flow Test, then see what CFM is at 28 inches of H2O.

example=> .700" Lift cam:
.700 Lift times .87 = .609" Lift
Flow head at .600" Lift , then take CFM at 28 inches and calculate HP potential with above formula.

.257 Factor = for beginning engine builders and engines near 10.0:1 Comp Ratio

.285 Factor = would be for Professional engine builders with wet sump pans, lightweight rotating assemblies, low tension great sealing rings, deep oil pans, etc. and excellent use of inertia/wave tuning with 9.5 to 11.5:1 Comp Ratios or 11.5 to 13.0:1 CR ranges without fully utilizing inertia/wave tuning effects

.300 to .310 Factor = Current ProStock Technology with dry sump, unlimited carburetion, High Comp Ratio, ultra lightweight rotating assembly, etc, and maximum use of inertia/wave tuning, etc, 14:1 to 17:1 Comp Ratios.