Bought a 87 Supra Turbo 1 month ago, and have not been able to drive it since I got the damn car. Since I got it, it blew the coolant all over the engine and the car overheated and the car shut off on me. Turns out the thermostat housing was not placed properly only had one screw holding thermostat and when I was driving home the bottom of the thermostat pushed out and blew coolant all over the engine, I had car taken to a mechanic who says the car had no compression due to a blown head gasket and when he removed the cylinder head he found 2 cracks in the head, so I gave him a new cylinder head and he replaced the head and head gasket but now is telling me that car still has no compression and that I need a new engine. Any suggestions on how to tell if the engine is good or not?