This is a Big Block truck. The motor is an upgrade from a 352- to a 460. But I purchased a BeCool radiator that is to cool a 700 hp motor. This motor is 520 hp. I have a friend coming over tonight to check the timing and he also talked about the jetting in the carb. I believe you are right on. The motor does not run as I thought it might. I do like to hear what you car guys have to say. I am just learning and I am very interested in how all this stuff works. If you have more ideas, please let me know. When I find this problem, I will post here the results so others can read and learn what cured the issue.