Olds1971

Needing a good solid running olds 350 from 1973, trying to bump up my compression on a 1972 olds 350

oldspackrat

I have a few mid '70s Olds 350 engines, all running. I'm in Indianapolis, call me?
Scott
c. 317-727-7041

red rag top

A 73 has more compression than a 72??? I find that hard to believe

oldsman72

'72 Rocket 350 compression.... 8.5:1

coppercutlass

Not more compression on the 73 but if you put 72 heads with less cc in the heads on a smaller cc dished piston short block like the 73 with a thiner gasket and maybe just a skim of the deck surface or heads you will have usable compression for a mild cam. 73 pistons are 14 cc 72 pistons are 23 cc the heads on the 73 have more cc's than the 72's .

Olds1971

I had read a post on here to get a 1973 motor and use the heads from the 72... Im trying to get 9:1 compression. Does a 1969 350 have 9:1? Theres a short block on here up for sale

coppercutlass

I belive the 69 350 the low compression engine was 9 to 1. To get true 9 to 1 compression you will need to measure the deck height and cc the heads as there is always variables from the factory.

Olds1971

would I be better off finding one with " 9:1" like the 69? or would it be better to use the 7a heads from mine on another

coppercutlass

If you are trying to do this quick and "dirty" I would buy one of the runners from oldspackrat and use the short block . Measure how far the pistons sit in the cylinders then call smitty at mj proformance and get some shim gaskets and have the heads milled down to get true 66 cc's assuming the pistons are appx. .025 In the cylinders this will net 9.04 to 1 compression. Again it can vary a bit like how far down the pistons sit at tdc in the cylinders , the head cc's .

Olds1971

Id like it to be done right. Doesn't have to be done quick by any means just trying to find a new project to work on.. My 1972s motor is about to make me slam my head against a wall

coppercutlass

Well there is many forms of right lol. If you plan on doing it right you may aswell do new pistons. It becomes risky to beat the **** out of 40 year old parts with loose tolerances . I learned that the hard way when I ran cast flat tops from a w31 after 2 seasons I started hearing noises ended up having 4 cracked piston skirts.

Olds1971

So 69 short block with pistons?

coppercutlass

Either will work to get 9 to 1 compression with the stock pistons.

Olds1971

Ok sounds good thanks for all the information <--- new learner here lol