Originally Posted by Alpha

True but it IS a good start if he doesnt want to turn a wrench on it. I compression tested a COLD engine over the weekend that came back 280 - 290 Warm it broke the compression tester Compression tester only went up to 300. Here is a very general guide

8:1 - 8.5:1 compression: 150-170 psi per cylinder
8.5:1 - 9.5:1 compression: 170-210 psi per cylinder
9.5:1 - 11:1 compression: 210-275 psi per cylinder
11:1+ compression: 250+ per cylinder (highly depends on cams being used)