I got one in my 84 Chevy 4x4 and right now I am having a hard time keeping it cool. I dont know if that is a problem with the 400s or not. I know that the one in my 4x4 has a mild cam and around 10:1 compression. I didnt build the motor or have it built so I cant tell you everything that has been done to it. I do have a set of Hooker Headers with 2 1/2" exhaust into dual flowmasters. It sounds good and runs good jsut need to figure out my overheating problem.