If I'm measuring correctly, the Y-pipe is 2'' OD and the muffler to resonator is somewhere around 2 3/8''. Does this sound right?

 

2.5. When I bought my muffler I went with 2.5

 

As per the almighty spike

 

Inlet and outlet. Sorry can't edit posts from my phone.

 

After the y pipe the exhaust is 2.5 inches wide. The y pipe on my truck was close to 3 inches. I had to search for a 3 inches flange when mine broke off. I don't remember the size of the cats though.

 

2.5'' size after the flange, alright thanks. Going to weld in a couple high flow CATS, loose the resonator and move the muffler back and add a nice tailpipe.

 

I need a welder. What are you using MIG? Wish I knew how to tig weld. THAT looks useful

 

I just got done welding in new cats and let me tell you it is not a job for the faint of heart. If you want a blow by blow I can oblige, but judging from your past posts I am hoping you will have serious help.

First of all, the y pipe tubing is closer to 2-1/8, if you get 2 it will be too tight.

Second, the aftermarket cats are longer than what you will cut out and cause some geometric problems when putting it all back together.

Third, the cat inlets and outlets are very thin compared to the y pipe and is very tricky to weld.

Fourth, the pipe pulled allover the place when I took it out and welded it, even though I very carefully control welded it once it was out of the truck.

Good luck, I have pics etc but seriously don't thunk this is a 1-2-3 done job

 

Over twenty five years of welding experience, railroad pump repairman, Marine Corp heavy equipment mechanic, life long auto mechanic, NO PROBLEM. Anyways, I'm convinced that the Y-pipe is going to have to go. I'm going to just run new pipe as duals all the way back. I'll salvage the pipe to exhaust manifold and just weld all the way.

 

Sweet. Then come do mine too!