1996 RCSB stepside, L31, HT383, 1.6 rockers, short headers - need exhaust recommendations

[DrunkenSailor]

While rebuilding my 96 350 (244k on the clock and found a bent rod, so worth it!) I swapped out the cam for an HT383/Ramjet350, 1.6 roller rockers, LS springs salvaged from my neighbor's 600/600 LS project (final lift is .460/.481) and short tube headers. Also doing an 0411 swap with tune and upgraded Spider injectors. The entire goal of the rebuild is to wake it up a bit while cruising around town, maybe doing some light hauling/towing as needed but nothing too ambitious.

Both cats are likely clogged and the muffler has a massive hole in the bottom so everything needs to go. I want to keep the truck 49-state compliant as I move every few years and don't want to pay to re-do this. Plan on keeping EGR for the same reason. This leads me to a few questions:

High flow cats or no? I didn't realize how (relatively) affordable they were - I was anticipating $500+ea but it seems you can get them for significantly cheaper. Manufacturer/model recommendations would help a lot here.

True duals w/ X pipe or 2-to-1 Y pipe?

Also need muffler recommendations - my practical adult side wants to follow the established trend of improving bottom-end performance while my inner teenager wants it to sound nice.

I'm completely ignorant when it comes to exhaust configuration but I've done plenty of reading on here/reddit and it SEEMS the general consensus 2.5" duals with x pipe, HF cats, and 2x mufflers. Don't know where I want to dump the exhaust (turn downs after the rear axle, 45s or 90s out the side, or straight out the back). Any vehicle-specific is greatly appreciated!

 

[L31MaxExpress]

Had basically the same engine setup in the 97 Express for a while. I kept the 3" duals to the muffler, used Thorley tri-ys that came with pipes already made to connect to the OE exhaust tubing, swapped in high flow cats, and a dual 3" in/single 4" out bus muffler and a 4" tail pipe made for a diesel GM truck.

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Ran good for what it was.

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[DrunkenSailor]

Had basically the same engine setup in the 97 Express for a while. I kept the 3" duals to the muffler, used Thorley tri-ys that came with pipes already made to connect to the OE exhaust tubing, swapped in high flow cats, and a dual 3" in/single 4" out bus muffler and a 4" tail pipe made for a diesel GM truck.

xc_hide_links_from_guests_guests_error_hide_media

Ran good for what it was.

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Yeah, Thorley Tri-Ys would be nice but definitely not trying to drop THAT much $$$ haha. Love the sound and really consistent acceleration, got up to 80 reasonably quick but would have loved to see a tach as well to follow RPM:MPH.

Any recommendation on HF cats, or is just about anything on Summit/Jegs/Amazon good enough for government work?

Can't decide if I want true duals (2x 1:1), 2:1, or 2:2 mufflers. Also still working on where to route the pipes after the muffler - duals out the rear looks pretty good on these trucks. Also considering duals out the pass side after the rear axle, and there's some part of me that likes the absolutely terrible idea of doing duals out the pass side just BEFORE the rear wheel lol

 

[PlayingWithTBI]

I was anticipating $500+ea but it seems you can get them for significantly cheaper. Manufacturer/model recommendations would help a lot here.

If you wanna be CA compliant you'll probably pay ~$500 each - they need to be CARB compliant. Some other states may require that too since there's a lot adopting CA rules. If youe truck came with 2 Cats, you gotta have 2 Cats AND they all have to be in approximately, if not exactly, in the same place. Some states require your exhaust pipes to stick out a certain distance so, they can hook up the sniffer but, FWIU that's mostly on OBDI vehicles.

 

[DrunkenSailor]

If you wanna be CA compliant you'll probably pay ~$500 each - they need to be CARB compliant. Some other states may require that too since there's a lot adopting CA rules. If youe truck came with 2 Cats, you gotta have 2 Cats AND they all have to be in approximately, if not exactly, in the same place. Some states require your exhaust pipes to stick out a certain distance so, they can hook up the sniffer but, FWIU that's mostly on OBDI vehicles.

No plans to ever live in CA (career reasons, mostly) but didn't realize more states were adopting CA standards. Likely moving to CO in the next few months, looks like they do bi-annual emissions testing for cars 81+.

 

[L31MaxExpress]

Yeah, Thorley Tri-Ys would be nice but definitely not trying to drop THAT much $$$ haha. Love the sound and really consistent acceleration, got up to 80 reasonably quick but would have loved to see a tach as well to follow RPM:MPH.

Any recommendation on HF cats, or is just about anything on Summit/Jegs/Amazon good enough for government work?

Can't decide if I want true duals (2x 1:1), 2:1, or 2:2 mufflers. Also still working on where to route the pipes after the muffler - duals out the rear looks pretty good on these trucks. Also considering duals out the pass side after the rear axle, and there's some part of me that likes the absolutely terrible idea of doing duals out the pass side just BEFORE the rear wheel lol

Converter flash stalled about 2,500 rpm and it shifted like 5,100.