Thursday I am getting my true dual setup installed. It will consist of 2.5" pipe with secondary cats removed and straight pipe put in place. O2 sensors will be mounted in them. H pipe into 2 original flowmaster 40's exiting opposite sides behind rear wheels with 22" long 4" tips. I will post video and pics when completed. :cheers:

That should sound great..........from the outside, lol. Just kidding, my mechanic friend is working on an old chevy 383 with a similar setup and I was drawn to it last night when he fired it up. I love the sound but you will lose quite a bit of low end grunt with that so you may want to consider 2" pipe with an X pipe in the middle and then larger pipe past the muffler(s). Good luck and happy modding.

 

I would only go down to 2.25 to the mufflers then 2.5 back. Would there be a big difference between 2.25 and 2.5 to the mufflers?

 

You're going from DISO to true duals, so you need to take that into consideration when sizing the pipes. If 2.5-3" is plenty for both banks then 2.5" for one side is overkill and will hurt performance in various ways (Backpressure, exhaust pulses and scavenging, etc). I wouldn't go more than 2.25" unless you're planning on going forced induction.

 

Is there a difference in sound volume between 2.25 and 2.5 back to the muffler?