Posted by John Paseman
One of the Mopar Magazines recently did a test on a smallblock (360 I think) and found about a 20-25hp difference between manifolds and headers. Not much extra HP for what you give up. If you have a set of good '68 manifolds, I would just stick with them. The headers will make a couple of more ponies, but they will be a bit louder and prone to leaks.
Having said that, if you want headers I will tell you what I used on my Bracket Race Charger. I bought the Hooker Competition headers with the ceramic coating. They are thicker than the super comp headers, but I wanted a bit more durability since they are thicker. I think the Hooker part number is 5903-1. They are 1 7/8 primary tubes and a 3" collector. The race car went an 11.68 @ 114mph last year with those headers, so they can support some HP! I got them on sale at summit for around $325 including shipping. Best deal on coated headers around.
Either way, put in a 2 1/2" dual exhaust with a crossover (H or X - your choice) and listen to other folks car to pick a set of mufflers. I used a set of hemi mufflers and a factory H pipe on my Street Charger and it is pretty quiet. I have 3:54 gears in my Street Charger.
The 3:91's will make it a bit louder at cruise, but not annoying. Louder mufflers may not be acceptable - but it really is up to you!
Think manifolds can't make power? All the racers in the FAST series (Factory Appearing Street Tires) are going 11's with full factory exhaust and BIAS PLY TIRES!!! Yikes!