1980 Malibu 350 stock compression ratio

[mobileaudio25]

What is the stock compression of a 1980 350 Malibu? I'm at 9.4:1 , is there any way to increase the ratio without a piston swap?

 

[80ECLT]

IIRC isnt the stock CR on these like 8.5: 1 or something low??

 

[CHRIS.O]

I don't know what the stock ratio is but yet you can increase compression by milling the heads, smaller combustion chambers, decking the block. Decking the block would require the engine to come out though so you might as well change pistons at that point. Also you could run a steel shim head gasket, I believe they are .015 compressed thickness instead of the usual .039.

 

[larryo454]

Hi a 58cc head and bump you some vs a 76cc head.

 

[Max Headroom]

I just took the compression from 9.28 to 1 to 9.81 to 1 with a head gasket swap.
I used a .015 steel "shim" gasket I got from a place called Engine Parts Warehouse in Baton Rouge, La.

The gasket is a steel shim and basically doesn't compress, so you have to be real carefull about torquing the heads down. I did mine about two weeks ago and had to retorque after about 8 hours of running time. I also had to raise the clamping pressure to 85 ft/lbs. Also, I had to use a LOT of thread sealer. Runs great now.

I changed the gaskets because the cam guy for the cam in the motor said I had to have at least 9.5 to 1 compression to get the cam to run. He was right; it made a big difference.

If you are already at 9.5 to 1, you could probably go with a .020 gasket and get close to 10 to 1.


http://www.enginepartswarehouse.com/