What size y pipe and exhaust pipe should I use??

[stunna p]

Im new here.....So hello!!

I have a 95 k2500 8 lug 4.10's, 350 tbi, (stock) Its a daily driver. I also haul a bit here and there. I want better mpg...period!!
I just bought hedman lts for it. I am planing to make my own y pipe, I assume the best size tube for the y should be 2 1/2? then I was going to do single 3in pipe to thrush muffler behind the pass tire.
Any forethought or recommendations to the concept. Thanks Stunna

[305guy]

Are you running a cat?

[cancritter]

anything other than single 3 in after y will be a waste of coin...would keep muffler in front of rear tire and dump exaust behind rear pass tire...

[stunna p]

No cat.

[stunna p]

is the cat gunna help mpg andperformance, or hurt it??

[305guy]

It won't gain you anything, unless you have emissions in your area..