I have a Blazer yr 2000 and I bought it because.

I have a blazer yr 2000 and I bought it because the intake gaskets went bad and let water mix with the oil. So I bought a gasket set. I flushed the motor out put new push rods because of surface rust put it all back together and wen I went to go start it. The motor turned over insted of it making a ra ra ra ra and starting up it makes a wine. Someone told me to do a compression test because the push rods have been replaced and maybe pumped up. What does that mean? I dont know much about cars please explain better.