My RCSB project truck has an LQ4 6.0L with 243 heads, 224/224-112 cam, obx long tune headers and dummy cats(6" resonators) with the 2.5" dual pipe Silverado SS pipe setup(No Y Pipe). When I originally built the truck i was in a hurry to get it going. I had a couple 2.5" 45* pipes, a 14" long 2.5" magnapack bullet muffler and some 2.5" pipe laying around. So i fabbed up a quick Y pipe and welded the single bullet muffler in and dumped it right before the rear axle. I have a roll pan so the spare tire and carrier have been removed and I have tons of room to play with. I like the tone the magnapack has, but with the single outlet, it sounds a lil funny with the cam idling. Its a lil loud/crappy sounding in the cab, but sounds mean as heck outside. Plus, with exhaust being dumped and having a roll pan, my tailgate it constantly covered in dirt and exhaust soot. I've been wanting to run a tailpipe on out the back of the truck to help with kn cab noise and soot all over my tailgate. Im wanting to go to a true dual setup so i can hear the cam a lil better. I am pretty good at fabricating exhaust and hangers. And i have a buddy with a pipe bender and my brother in law is an amazing welder. I have access to a plasma cutter, sawzall and mig welder, So ill be fabbing the new exhaust myself. I currently have a couple more 2.5" magnapacks and a 18"ish long 2.5" dual inlet dual outlet magnaflow laying around. Here are the two setups im considering:

1) h-pipe right after the midpipe connections with each pipe having a 2.5" 14" long magnapack and exiting behind the rear axle.
2) h pipe right after midpipe connections withe the 18" dual in/dual out magnaflow with tailpipes exiting behind the rear axle.

Which do you guys think would sound and perform better? Im looking for a deep, lopey rumble but not headache loud in the cab. Right now i can carry on a comfortable conversation in the cab cruising at 60-70mph, and id like to keep that. But i want that mean "drag car", be very afraid sound outside the truck.

 

I also have tons of 3/16" steel strips and factory style hangers laying around, so supports/mounts arent a problem either.

 

Nobody has any input?

 

Food for thought.

I'm running OBX style headers, cut the Y pipe out, X-piped it and ran dual 14" magnaflows (ran dual 40 series flowmasters first) that dump behind the axle. It's definitely got that rumble you're describing, but I don't know if it's the way it's dumped or what... but there's some pretty good noise in the cab running down the highway.

 

Thanks! Im thinking the h-pipe will eliminate some of the rasp i have now with the magnapacks, in favor of some rumble.