Conversion for cutting heads

[67racing]

Need to get a set of heads cut down, and don't remember the conversion for if you cut .01 off is so many CC's. I think Jay Smith had told me about 4 years ago, but I don't remember. Thanks They are 39cc now and need them cut to 34cc.

[KIRCHNER]

I WOULD start at .050 and cc. too many factors to compensate for.

[Merc 2.5]

My guess would be that u have a c5 head with 39cc? If so I'll have the # your looking for in a few. Waiting on my block guy get back with me , I'm having same thing done,I wanna say he said 40thousan off the head,but I'm not 100% positive just yet

[KIRCHNER]

JUSTdid my 2.4 was 38cc cut .065 now 32.5 cc

[greatwhite85]

I’ve been trying to figure this out too. Since the chambers are pretty much a perfect cylinder I would think it’s the same equation as measuring the displacement of a single cylinder engine with a 2.27” bore and a teeny-tiny stroke. Then I just ask google to convert cubic inches to cubic centimeters. Here’s what i’ve Come up with;
bore x bore x stroke x .7854
@ .050 =.202 Ci = 3.31 cc
@ .065 =.263 ci = 4.31 cc
@ .080 =.323 ci = 5.29 cc
I think I’m on the right page, can anyone else tell me if I am missing anything?

[nelson edens]

This quote by Jay Smith on Biggerhammer.com

MOST loss foam embrelled 1 piece heads that are stock and NOT A DRAG or F1 motor the formula for cutting is as follows :

For every .010" that is removed from the head surface the cc 's will be deminished by .7 cc's
Example: .040" removed will diminish the CC's by 2.8

[Umassot50]

Volume= pi X r squared X h

Where pi = 3.1415927
r= radius of the bore in centimeters
h= height to be cut off in centimeters.

1 inch = 2.54 centimeters.

This gives volume in cubic centimeters.