I guess you need to figure out if you want max performance or just something that will work and kill the performance.

I am using Stahl Headers in my 68 Dart. They were on a low deck with 440-1's. They are 2 1/8 to 4 inch collectors. They are real close to equal length I think with in and inch. There are 3 out and 1 in on both sides. no dinging needed. The only adjustment made was when I went to the new style master cyl I have to move on of the tubes around.

Pics are in the tech section of bigblockdart.com


forgot, they will run you just over a grand. they are slip fit and very, very nice.