I had a 24" magnaflow put on, custom y fabricated. Muffler inlet is 3" and what looks like dual 3" out the back of the muffler to the 3" tips behind the wheels. Is this too open, not enough back pressure etc? I ordered the Airaid MIT and have a K&N drop in and a SC Flashpaq. What R ur thoughts am I alright or am I gonna do some harm. Should the rear pipe diameter be reduced?

 

I have the same set-up from the muffler forward, after the muffler I wouldn't think it would matter what is on there. The cats and muffler should provide plenty of backpressure for you.

 

I was wondering the same thing as I have some 3" pipe lying around. Was gonna get a friend to bend it for me, but wasn't sure if I should go down to 2.5" pipe. Gonna go with a cherrybomb extreme with a 3" inlet and 2.5" outlets. Kinda was hoping to get fittings to go up to 3" pipe all the way to the end of the truck. Also, what benefit is the magnaflow y-pipe or would it be fine to go with a dual inlet and duel outlet muffler and not run a y-pipe?
Thanks!...and all have a great Labor Day!

 

Unless you guys are going with a true dual setup, 3" is fine, other wise, if the engine is stock and you want to go with a true dual setup, stick to a 3" in 2.5" out