I usually allow +- 10% of the gauge readings as that is within most gauge tolerances but 65-70 psi is normal for these engines as they do have bump decompression. This is usually on the exhaust valve so that more clearance on that valve decreases the bump and increase compression at start-up.
Briggs don't publish minimum compression numbers because this decompression but I have through experience found around 70psi is a normal good reading for these L-heads.
