Dizzy Kobe Traven

I just got my first car from a friend and the engine either needs to be rebuilt or swapped he says it has no compression he said it was valves but I wanna see if its a head gasket and most of the small stuff like lights and radiator were sold I got it for free and im here to see if I'm better off engine swapping or rebuilding it and if there are any enter changeable part for the motor to try and save cost