Ok, so LT's is next in my to-do's list. It's a 6.0 HO LQ9 (I think) motor in a rcsb. The exhaust is all off the 6.0 HO truck, so whatever size exhaust comes on the 05 HO trucks is what I have. Right now, I have factory manifold, cats, and pipes, but right under the bed before the rear end, I have a Flowmaster 40 Dual in/Dual out dumped. It sounds really good and I plan to re-use the muffler when I do the lt's. It's all dual pipes until the 1 muffler. Because it's going to 1 muffler, would I benefit any from ptting in a H-pipe before the muffler? Is the stock piping 2.25" or 2.5"? I'm planing it to be lt's with fake gutted cats, dual seperate pipe til muffler, then dual dumps. Will they factory piping restrict me any? All I have is bolt-ons. I should be good right?

 

Simple answer would be to replace the Flowmaster POS with a Magnaflow the same size which has an X-pipe already built into it.

http://store.summitracing.com/partde...5&autoview=sku

 

x2, get rid of the flowmaster. Id just do an ory with a bullet and a magnaflow.

I have a 12 inch bullet and a 5x8x14 Magnaflow on mine.