Currently swapping my 351M to a 400 block, and was wondering the advantages / disadvantages of doing dual exhaust...

From the looks of things, I have to stick with the 2 into 1 manifold, then I could possibly branch it out. My truck has the optional / stock 2nd fuel tank, so that would make it extremely difficult to dump it straight out of the manifold back.

What do I gain by branching with duals from the cat all the way back?

--- Goobz!

 

It will weigh and cost more than a single exhaust, and will offer no power benifits.

You gain the look of duals, nothing more.

 

That was exactly what I wanted to know! That's what I thought. Now, the ? is, since the truck had like 1 3/4" exhaust, I want to keep it 2 1/2" all the way back. Any problems with that!?

 

2.5" would be great.

 

a tuned dual exhaust will flow better than a single exhaust. your forgetting that they used to put duals on the old muscle cars as well right from the factory. Plus dual exhaust just sounds hella cool.

 

Reread the first post and see that he only has a single cat he wants to keep. No possibility for true duals

A single exhaust can flow as well as duals, its all about pipe size, velocity and flow potential. I will agree true duals sound good though. I have heard some awesome sounding single exhausts also.