i'm running dual 3" on my formula. it's an LQ4 with an LSR 239/247 .624 .624 114. granted, it's a giant cam, but i picked up retarded power going from a Y pipe to dual 3" without losing any torque.

i agree it's too much for a 4.8 unless you're spinning like a million RPMs.

 

I'm running that same cam (219/227 607/614 112lsa) and 2.5 true duals on my 4.8 and trust me you will not be disappointed. The cam alone way outperformed the tr220 I had in previously even untuned and was amazing once I had it retuned. IMO, 2.5 true duals would not be overkill. 3" maybe so but not 2.5". My truck runs noticeably better with the true duals compared with the ORY and single muffler. Speaking from experience here.

And BTW, the cam sounds KILLER

 

Yes it does! I love the sound of that cam lol

Not to hijack the thread but would snowba11's cam be too big to go FI at some point? I'm looking at a cam similar to that and I'm likin the specs on that better haha

 

I would say it's not an over kill if u don't go over 2.5 inches ive been wanting to do that exhaust my buddys Nbs 5.3 has h/c and running that exhaust and it flies 12.20 @ 112.9 mph n/a so i dont think its affecting it...

 

I've got True Duals 2.5inch on my 4.8,and both the mufflers come out right at the bed/cab line...Well I finally got an x-pipe welded up a few weeks ago and it seems like it made adifference in power..But I did get alittle different sound out of it also...

 

I have american racing headers and pulling the ory off to go duals so if you need one hit me up if you go that route and save your self some bucks but if was you would go duals. I hate the single exhaust tone you get from it and I now have long tubes ory to single 3 inch to a borla pro xs single in dual out 2.5 dual out the back and I dont like the raspy sound it gives off. Sounds good cruising and at idle it is very tame almost quiet but stomp it and sounds like glass packs I put a pair of resonator tips and helped a ton on noise but still raspy and I want that more muscle car sound like when you put a good exhaust on a mustang they sound sweet. Now got the late model single exhaust camaro sound and I hate it so going dual 2.5 with x pipe or one of the x pipe mufflers with 3 inch due to restriction at muffler. I am going with a supercharger on my 2007 z71 tahoe and why I am doing all the exhaust work.