I am going to be building a custom Y pipe for the ooker LTs and T56 trans and I need some advice on which diameter pipe I should I use. its either 2.5 or 3" I will get a little more room with the 2.5" pipe and I will be able to use the flowmaster 2.5 into 3" y collector but will the 2.5" pipes kill a lot of HP? I plan on running a 3" intermediate pipe from the y collector back. My engine specs are in the sig. Flowmaster doesnt make a y collector that goes from 3" in to 3" out. They have either 2.5 in and 3 out or 3 in and 3.5 out. WIll I really choke up my engine with a 2.5" y pipe?

 

Mufflex has a "Y" pipe that will bolt right up to the #2210s. It has 3" tubing that goes into a single 4" outlet, you can bolt up a 4" system, or put a 4", to 3" reducer on, to bolt up to a 3" cat back system. If you are positive that you want to build it yourself, I would go with these diamaters. Mufflex charges 250.00, IIRC. Personally, I would go with the 3" on a 383.

 

you know,I would go with the Mufflex y pipe but I have read to many people having fitment issues. Plus Im not even sure if it is designed to workunder the crossmember or not. if itis then I cant use it. I just dont have the room for it under the crossmember. I priced out the stuff I wil need to do my own and it comes out to just over $230. This is all stainless pipe too.

 

If running a 3" I-pipe, the 2.5" prolly wont hurt you. If you got the room for 3" I would build a good "Y" if you cant find one. I wouldn't run the mufflex "Y" without the full system, no sense in hacking up a high dollar piece or running reducers when you could build what you need cheeper and flow better.

 

I bit the bullet and bought the mufflex Y and the 4" cat-back. I will try to finish installing it tonight. As for moddifications, I had to cut one pipe, and weld in a 4" long piece, I then flatened it a bit and it all tucks real well on that side. Tonight I think I need to add 2 3" long pieces to get the moded parts back to where the Y pipe wants to be. Then the cat-back should go on fine I think.

I have no pics, but I will update my CD site after Wed when I should be totally done.