Q about exhaust pipe size

[commando1]

What you REALLY want is a single system.

Not the factory crap, what you want is a system that merges the both banks correctly and smoothly, that is worth way more performance all around then a dual system joined.
Done correctly you'll pick up mpg and perf and it will not sound like crap.

You would be better off with say 2" into a merge pipe and bumped to 2.75 and into a chamber muff that is placed correctly in the exhaust.
Back pressure isn't what you're after, you don't really want back pressure you want constant scavenging, and you can't have constant scavenging from a dual, now the issue is getting the merge in the right location and then the muffler
.

I went this route and I'm glad I did.
I had a NOS Y-pipe , NOS muffler saddle, NOS tail pipe saddle, and NOS tail pipe hanger .
that I accumulated over the years for the right opportunity.
First system ever where everything fits perfectly and easily. And it is so close to OEM that you make apologies to no one.
I bet I can drop it and install it a dozen times in one hour.

Just removing the Cat cork did 90% of the improvement of a custom dual H-pipe 2 1/2" system.