Thanks to all for your answers. I,ve decided to put some heads on and a diffent intake. Now this question. The 327 has headers on it. I,m thinking about converting to stock exhast so it will be a little queiter. I know I will loose some hoursepower. But it all so viberates when at a stop and ofcourse its hard to change plugs. The heads that I will be putting on are off a 350. And the plugs are the 5/8. What are some comments on that. Thanks, John.