Ok so I got a different pickup. A 1999 1500 extended cab long box with the 5.9. I've heard that the bigger the pipe the deeper the exhaust. I've been calling exhaust shops and they've been split both ways on the issue of losing power. I'd do a cat back y-pipe with 3inch pipe and 4inch rolled tips ( 18 inchers) out at 90's. Has anyone on here ever ran 3inch pipe and noticed a difference on the power end? my cat would still be 100% intack so I figured that'd give enough back pressure.

 

Going to three inch behind the cat will make the tone deeper, which will be further modified by whatever muffler you choose. You MIGHT lose a little low end, but, it ain't gonna be much, and you MIGHT pick up a little mid to high end power, but, again, it ain't gonna be much.

 

Thats exactly what I was curious about I want that deeper tone and I really didn't think it'd lose a whole lot of power. But I figured I'd ask the experts I've had all different kinds and variations of exhaust but nothing ever with pipe bigger that 2.5 in.
Thanks!!

 

ive got 3 inch straight pipe on my truck from cat back and it has a nice bassy rumble to it and dont pop and cackle like the smaller pipe when you straight pipe and i still have cat fully intact and i couldnt tell any loss at all on low end and its got just a touch more power it seems in the mid to high end.

 

3" was a great choice for my truck but you wont see full benefits until you address cat and y pipe as they will still be the choke point.

 

ive got dual 2 1/2 from where the cat was into 2 magna flow high flows, into two thrush glasspacks also 2 1/2 in and out, dumped right before the axle. it has very deep tones and gets a little cackly around 3-3500 rpms. still have the stock down pipes or y pipe (not really a y any more) gonna cut em out here soon and go with 2 1/2 all the way. eventually put some shorties on also.