What is my compression ratio CR?

[irvin]

I have a 95 GT with Trick Flow top end kit installed. The bottom end is stock and I know the factory CR is 9:0:1. Does the CR change after the heads swap and what would it be?

 

[97modgt]

It can change. You need to know if the decks on the heads have been shaved down. That will make the ratio go up for sure and some people do that for a little extra compression. Are the heads used? Also look at the specs compared to the stock heads.

 

[BadA55f0Xxx]

the compression shouldnt b different its a direct bolt on kit specifically made for the stock applications and the pistons are still the same. . .but im no expert thaats just my 2 cents

 

[TERROR]

its all depends on the volume of the combustion chambers on the heads, do you have a part # on the kit

 

[irvin]

No I did not shave the head. I bought the kit brand new from Summit.

 

[irvin]

According to trick flow, the combustion chambers volume on the heads are 61cc, and the part # for this kit is TFS-K514-360350B

 

[91Notch]

The TFS TW have smaller chambers than the stock 64cc E7 heads so the c.r will go up, but not much really.

 

[BadA55f0Xxx]

so then C/R can change from heads? not drastically can it??

 

[svtnotch]

Cr calculator http://www.kb-silvolite.com/calc.php?action=comp

 

[TERROR]

so then C/R can change from heads? not drastically can it??

combustion chamber volume and pistons are major variables in compression ratio, with those heads your not looking at much of a change, maybe a tenth or two of a point thats about it