Here's an article on X and H pipes.
http://www.superchevy.com/how-to/ex...sepower-but-which-is-best-for-your-ride/H pipes quite the exhaust sound noticeably.
Joe H, an inexpensive coating option is flame sprayed aluminum. The flame sprayed aluminum on my '36 Chevy PU exhaust that I restored in the early 1970s is a little bit dirty now from road grime but is still intact and has protected the pipes and muffler from rust.
In the summer of 1967, when I was a college kid, I had a summer job welding at Doug's Headers. Since then I've built several sets of tube headers for myself and others and I've had no leakage or blown gaskets. My present street rod, a sbc powered '32 Ford roadster has block hugger tube headers that have been installed for 13 years and over 21,000 miles with no leaks. The key may be using quality gaskets. The ones I used were in a Fel Pro set. The headers do radiate a lot of heat that makes the under-hood area like an oven. To compensate I built a cold air ducting system to feed the air cleaner cold air from in front of the radiator.
