2 months of talk on here, not even 9:1 compression yet?
I will solve the mystery. find some older heads in good running condition, and bolt them on with a thin .028" corteco head gasket. #1-7
You will be around 9:1 just doing that.
All you would have to do is enlarge the push rod hole clearance with a stone grinder or carbide burr to make up the difference between the 45 degree and 39 degree lifter bank angles depending on which # you find.
Olds 350's are mean. They just need compression, and a GOOD VALVE JOB.
If you do that, and get a half ass good tune on it. I'll bet it runs 13.5 all day long in a g body with some decent rear gears and headers.
Bump the compression up to 10.5:1 with flat tops and a 230 ish cam @ .050 and you could be running high 12s.
GO! Do IT!......NOW!
You're damn right I still like old, boxy cars.