Quote:

I'd just hate to mess up this engine by over heating valves and so on. You guys are right about the horse power tho, I haven't upgraded the intake, carb or the heads so I do have room to grow. However, it's a street car and I'd like to build it to be durable.



How do you figure you'll overheat valves by the size of your exhaust system? The only way you'll cause problems for the exhaust side of the engine is if you don't run enough timing. The fuel will still be burning as it goes out the exhaust.
I think 2.5" exhaust will be plenty for you. It's easier to package under the car and you'll pay less for the tubing and everything. Well typically you will.