My last build cranked out 150 across the board(give or take a few).Measure the compression PSI and divide by 14.7 and that will give you a good approximation. Remove all of the spark plugs to get it to crank as fast as possible and give the most accurate number. stock 9:1 compression motors usually crank around 125 psi, much more than that is getting to be a bit too much for a supercharger on pump gas.
Tom I tried to tell them. I don't care what they do. I was just pointing out mis information, so others do start to think the same way.
Dude you look at it this way. You could have a 12:1 CR and only have 125 PSI cranking compression. Compression ratio is a fixed Number. It doesn't change unless you modify stuff like the Combustion chamber, head gasket thickness,Piston compression Hieght, Bore size. Your thinking is totally wrong.Thanks for all the input guys. At least I know that if its higher than 150 its likely that it is not the stock 9:1 ratio. I will also disconnect the fuel pump relay so fuel will not affect the measurements.