[Glens64chevelle]

Hey this maybe a lame question but I was wondering about the possible compression ratio of my motor. I had the heads off this weekend and I did not see any part numbers so I cant tell but maybe you guys have a idea. My 396's pistons have a a 3/16" dome to them and I have 3933148 heads which are 112cc's according to mortec and assuming that the block and heads haven't been decked. What do you think ??

 

[Kevin R]

Here is a good website to figure CR You just need alittle more info is all
http://www.rbracing-rsr.com/compstaticcalc.html

 

[kettbo]

I'll take a swag at it....
The standard 325 and 350 horse small-dome piston like yours continued on into the last of the 402 run in 1972....
Early chambers, pre 67, were about 98cc, CR close to advertised 10.25:1
By late 67 the chamber was semi-closed, 101cc, CR closer to 10:1
1969 the 265 horse 396 for Fleet use got the 148 heads at 112cc...I'm guessing 9.1:1

http://kb-silvolite.com/performance.php?action=details&P_id=105

This site says 9.04:1 with the 112cc #148s

 

[Glens64chevelle]

Cool George I was hoping someone would have a educated guess Thanks

 

[Dave]

Cool George I was hoping someone would have a educated guess Thanks

Hmmmmmmmmmmmmnnnnnnn

 

[kettbo]

I be edumacated :yes:

 

[66 Buick Special]

Glen, how far below the deck surface are your pistons?
Do you know if the block has been decked?

 

[FRYNTYR]

Anyway you look at it, comp sucks on that one. A 396 needs the comp to help out alot more than a 454. Torque difference is quite a bit.

 

[kettbo]

Doc is hinting at you getting some 1966 closed chamber heads then having them shaved