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Wanting to Raise the Compression

733 Views 4 Replies 3 Participants Last post by  demonstang76
Alright guys i want to make myself 100% clear on this before i start buying stuff i cant use and this site hasnt let me down yet

I have a 65 289 block and bottom end, with hyper. flat top speed pro pistons with 4 valve reliefs (+8cc). i have ported 302 D0OE heads with 2.02 and 1.6 valves (i was told 60cc combustion chambers). Im installing a X303 cam(.542 lift). By the looks of the heads with the 2.02 intake valve i highly doubt it could be milled down anymore. if it was the head, if sat flat, would sit on the valves lol. so im wanting to get the compression ratio up too at least 10:1 in order to do that with the gasket and pistons i have i need to drop at least 4cc's of combustion chamber to get too 10:1.

Now with all that said anyone have any experiance with pistons i could change too that will give the 2.02 valves enough room to open but raise my compression a little? Just so everyone knows the engine is currently in a car with heads so i cant get the dimensions of the valve reliefs or piston clearance myself. any ideas at all will be appreciated Thanks in advance
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thanks for the much needed bubble burst cindy, apparantly i had an urge to split my 289 down the middle. i went back and looked and i need alot more then 5cc to push 10:1, i entered +8cc on dome volume and relief volume, i actually am more around 8.5:1 right now and only way im gonna get that many cc is to redesign my piston and heads setup, no thanks lol
Hyper pistons sounded good in high school when i was doing the low budget rebuild for a senior project, sadly i wish i was aware i would have came out cheaper just to get forged to begin with. i looked at the numbers on dyno sim, with all my information perfect im still looking just over 350 to the fly with lower then stock compression... ill manage somehow :p
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