how hard is it to do a compression test on an engine outside of a car?

my buddy is selling his early 80s sbc 305 for $450 CDN. it has been rebuilt with new pistons, lumpey cam, hard top valves (i think thats what it is).. it just needs a carb, but i can use mine..

so he's bringing it over on monday, and i wanna know what i need to do a compression test to make sure he aint ****ting me about being like new. what should a new motor push out for psi?

 

Umm you need something to turn over the crank and a stand to hold the engine (do not use a pipe wrench on the end of the crank, so dink did that to my 400 crank) Also I believe the compression from the factory was 9.5:1

 

It's easy to do on a chevy if it has a flywheel on it as the starter bolts to the engine, I've done it using jumper cables and a wire to engage the solenoid, hard to tell about what the compression should be as the cam affects what it will be, should be 130-190 psi, biggest thing is to have all the cylinder close to the same, if 1 or 2 cyl. are a lot lower than the rest you know you have a major problem. Make sure if it has carb. to block it open when you check so it will get enough air