head CC vs .0XX off

**George C** · 02-06-2007, 09:09 PM

what is the given rule for how much CC drop you get for every .010 off a head?

**Pure Stock** · 02-06-2007, 10:32 PM

On a stock E7TE cylinder head, cutting 0.10 off drops the cumbustion chamber size from 64.00 cc to 62.40 cc. Don't know how much .010 will effect combustion chamber volume though.

**George C** · 02-06-2007, 10:42 PM

.10 is alot!!!!!! or did you mean .010?

just know that my heads are 69.8cc and i had them milled .030 and going to run a .040 gasket where stock is .060

so thats a total of .050 off...im trying to figure out what hte CC on the head would be

**Pure Stock** · 02-06-2007, 10:45 PM

.010

Good catch. I was quoting The Official Mustang 5.0 Technical and reference manual. There are more mistakes in this book than I made at 2:00 am leaving a bar!

**George C** · 02-06-2007, 10:50 PM

thats showing like 1.6 so even at 1.5 for every .010 off

5 X 1.5 = 7.5 which would be around 62.3cc which i guessed would be around 63cc

im just tying to figure out my SCR, since they say 10.6 scr with a 67cc head

but not sure if they get that number with a .06 or .04 gasket..stock is .06

**George C** · 02-06-2007, 11:05 PM

someoen just posted over on tech saying almost the same thing...

.010 = 1.667cc off

which the math comes down to 61.46cc with a .040 gasket and .030 off the head...sotck head gasket is .06

so .050 off = 8.33 off 69.8 = 61.46cc

os knowing thta info, i believe im well over 11.1 SCR

makes sense why i have more resistance turning over this 408 with one head on it then i did with my old 11.1 364

any idea where teh SCR is sitting with those numbers

i know for a drop from 72cc to 64.5 cc it raises the SCR 1 full point thats a difference of 7.5

my difference is 5.5 so from 10.6 and that much increase should put me close to 11.4 scr

anyone dissagree on these math numbers?

**wick** · 02-07-2007, 05:46 PM

For every .010 you go after the initial .010 you begin to loose because the chamber is not a square cut. Its more of a cone shape. So you would need .020 to get what .010 would get after the first cut. Follow me?

**383taman** · 02-07-2007, 06:48 PM

Quik there is a great auto math calculator on www.smokemup.com. cost a couple of buck to join but very worth it.It also so has the best practice tree.