Im going to look at a motor for my 5.0. The motors out of the car and supposedly has 43k on it. now obviously im going to spin it by hand with the crankshaft to make sure its not seized or jammed. But isnt there a tool you can buy/rent to test the compression of a motor? If so can it be done on a motor thats obviously not startable? How do you do it?

 

only way to perform a compression test would be engage the starter uy it low and take your chanceswith a direct voltage source and perform a test on each cylinder.. other than that you could buy a leak down tester = would need compressed air present to make gauge work and roll each cylinder to tdc and check cylinder leakage but IMO buy it low and take your chances