71 340 Compression Test

That only works for certain cams so is not an 100% accurate conversion from compression pressure to SCR. And I made a mistake above anyway (which I corrected). My old rule was to divide the psi by 20 and then add 1. So 200 psi would be more like 11:1 SCR.

YMMV (Your Mileage May Vary... which is an American expression saying that your results may be different)