[74Grandville]

Originally Posted by 77 TRASHCAN

I calculated the compression ratio on my 1970 350 using 6 cc's dish for reliefs, .020 in hole with the 90 cc chambers, got 7.74:1. A long way from the 8.8:1 factory advertised...LOL no wonder I could run 44 degrees total timing and NOT make the thing ping. Has a 066 cam in it...

I had a stock 70 350 and cc'd the heads about the same "89cc". with the stock cam it used to pump around 135psi i think.

[77 TRASHCAN]

Originally Posted by 74Grandville

I had a stock 70 350 and cc'd the heads about the same "89cc". with the stock cam it used to pump around 135psi i think.

I was doing some carb work on this 350 currently in my car. It pumped 125, although engine was cold.

For some reason, a few years ago I bought a set of 17 castings. I was hoping for a little higher compression head for a 350. The matched pair both measured 83.5 cc's. Better than the 11's (which I did not know till this thread, I did not measure mine when doing my build for some reason)
The 17's would get my 350 a fuzz over 8:1 coming in at 8.18:1 LOL