compression
 

i want to test my compression but dont know what i should be getting

Per the GM FSM. "The lowest reading should not be less than 70% of the highest reading, and no cylinder should be less than 100 PSI."

thanx man

whats the max so i know what size gauge to get

GM does not publish the max limit. Just get a gage for gasoline engine use, and it should cover just any engine. Diesel gages go much higher and can cost more.

i was planning on going to northern tool and getting a 200 psi i dont think it will go any higher than that if 100 is absolute min ant the car is 15 years old so im sure its not as high as brand new any chance anyone knows what the thread is on the plugs