1967 Chrysler 300 fast top, 440 engine. It seems to run ok. I think I may have a heat soak issue with the edelbrock 1411 carb, but going to address that soon with a carb kit and a spacer. Hopefully that helps, but under hard acceleration I get this clatter..... I can't for the life of me figure out where its coming from. It sounds like its more toward the rear of the car. While in park I can rev the engine and it doesn't happen. At first I was thinking it was the pistons but since it doesn't do it while in park that would lead me to think its more transmission issues. The trans doesn't feel like its slipping when this happens, as the car continues to pull hard. So i thought maybe its something in the exhaust... but again it doesn't do it when its in park. So what am I dealing with?