Currently my truck is equipped with the factory 402 that has various mods. An Edelbrock performer intake, a custom built and tuned quadratoilet (That came on the truck stock), a custom ground RV cam, the heads that have been reubuilt and gone through that are hooked to port matched manifolds and 2 1/2 exhaust pipes with dual turbo thrush mufflers. I've been thinking that having a built carb, aluminum intake and heads that have been built hooked up to cast iron manifolds seems like it makes the mentioned work somewhat redundant. At some point I'm going to get longtube headers, 3 inch exhaust pipes, some type of x-pipe and dual Black Widow exhaust (Or maybe some type of straight through exhaust if I can't afford the Black Widow's) and I was wondering, what kind of tuning would I have to do to make the most out of the new exhaust system? I'd assume some type of jetting change, but I'd like someone's expertise. Any and all help is deeply appreciated