Project... Tinker !!!

[lukecp]

Originally Posted by BurnoutNova

what kind of pistons does it have? they looked like flattops in the picture. and especially with 60cc heads that should be around the 10-10.5 mark, right?

i have 64cc heads on my nova with .125" domes and its supposed to be 11.5:1

He has a 283, so it is compressing a lot less volume into the chambers, so it will have a lower compression ratio than a 302 even with the smaller chambers.

Possibly shave the heads to raise the compression? That would cost a few bucks but may bump it up a little bit. 283's are a great sounding engine...I had a buddy with one in a '67, and for some reason it sounded distinctly different than any other SBC I've heard.

[BurnoutNova]

so now you want more compression, when you did these mods to the heads to lower compression? im not sure, but arent stock 283's around 9.5:1 with 58, or maybe even 64 cc combustion chambers? i'd say 9.5 or even 9:1 should be a good compression ration to shoot for. i have ran 92 octane in my car, but for the most part i run 100 octane. i havnt bought it for a few years, but last time i checked it was about $5 a gal... and that was atleast 2 years ago.

another thing to maybe consider is some real thin steel headgaskets. im not sure but they might raise the compression by .1 or .2?

[BurnoutNova]

heres a compression ratio calculator... not sure if you already knew about this one. it seems pretty easy if you measure your stuff, gakets, ect

http://www.csgnetwork.com/compcalc.html

i get about 9.5:1 with the stock 3.875 283 bore, and a 3" stroke... assuming the piston has no dome at all, and assuming theres a little bit of deck clearance (maybe .010-.015"?), and a 60cc combustion chamber, and .025" thick head gasket (pretty thin, i think most sbc head gaskets are more like .045")