hey...got a quick and easy one

what is stock compression ratio for an 86 305 TPI?

Thanks

 

You will find your answer in the "tech data" section on this home page. (9.5:1)

 

hm...thats what i thought it was
so here is my problem
i'm rebuilding my 305tpi...but i'm strongly considering putting in
hypereutectic .020 domed pistons...does anybody have any idea
how much this will raise my ratio? and what octane gas i might
have to use?

 

A .020" dome will only raise you by .4 at most, so you can use pretty much any gas you like.

The factory 9.5:1 ratio is very optimistic. You'll be lucky to be at 9.5 with the domed pistons.

 

hm ...thats actually just the answer i wanted to hear

thanks!