340 Static Compression Numbers and Test Procedure

Something to think about;
1 degree change in cam timing works out to about 1.25 to 1.5 psi cylinder pressure. So a 3.5* change (about 1 cam size if both are straight up), is ~5 psi difference. To drop the pressure from 200 to 165 is 35psi. That's a lotta lotta degrees.How many teeth on a sprocket?

Nat said

I had a 34O with 195 cyl pressure compression was 11.4 ran well on 93 octane , would ping with 89 octane .it had alu heads if that makes a difference . Not sure the cam it had but was nothing much as it had good vacuum for the power brakes .
Good luck with your 340 those are good healthy numbers for cyl pressure

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Yes it does make a difference.
with aluminum heads;
You are at the top of the scale there; the highest reported pressure I have seen on FABO is 200 on best pumpgas with aluminum heads.
I have run my 367 at up to 185 psi on 87E10 with full timing.