I am building a 6L that will have about 450 Flywheel horsepower. Long story short, is a small motor such as this going to even benefit from dual exhaust? I am at the point I need to order out my long tube headers and need to know if I should order the true dual kit or the off road y-pipe that goes into my existing 3.5" catback. If you have some good exhaust reading I should do, please post up a link for me.

 

when 2 cylinder banks are present

 

Would you tell someone the same thing who had a 2.8L chevy V6?

 

A single 3.5" is going to flow similar to a dual 2.5". Most of the time there is no room for single 4" so dual 3" is the next step up. For a 6L a single 3", 3.5", or dual 2.5" would all work fine. A lot of flow can be gained or lost depending on which muffler is used. Straight through is the best but can be loud.