Any dual to single pipe products specific for gmt400’s?

[Eman_Odg]

I have a 99 suburban and I decided I wanted a carven tr muffler as I personally love the way they sound. The problem lies when my truck comes “true dual” from the factory. The muffler turns it into 1 pipe but I’m wondering if there are any products that convert these 2 pipes into 1. I’m not interested in running dual carven as this truck is not something I can justify spending that much money. Exhaust shops can probably make their own but will most likely charge me significantly for the work. The pipe is 2 3/4 if that helps.

 

[Eman_Odg]

I’ve seen Lawrence LT tolman use one but had to modify it significantly as it was not to the dimensions of a gmt400. Most likely a universal part.

 

[Erik the Awful]

Two 2.75" tubes have a combined cross section of 47.5 sq. in.
3.75" tubing has a cross section of 44.2 sq. in.
4" tubing has a cross section of 50.3 sq. in.

If you have dual 2.75" exhaust, you'd need to go to a single 4" pipe to maintain flow, BUT we know that exhaust flows in pulses, so you could probably get away with 3.75" tubing, but it won't be optimum. Your big problem is going to be finding any 2.75" or 3.75" tubing pieces. If you neck the pipes up to 3", there's a 3" to 4" collector for $65 from Flowmaster. I don't think you'll find cheap solutions when you're dealing with 4" diameter stuff.

Flowmaster Y300400 Flowmaster Scavenger Series Y Collectors | Summit Racing

Free Shipping - Flowmaster Scavenger Series Y Collectors with qualifying orders of $109. Shop Exhaust Pipes, Y-Pipes at Summit Racing.

www.summitracing.com

 

[L31MaxExpress]

Two 2.75" tubes have a combined cross section of 47.5 sq. in.
3.75" tubing has a cross section of 44.2 sq. in.
4" tubing has a cross section of 50.3 sq. in.

If you have dual 2.75" exhaust, you'd need to go to a single 4" pipe to maintain flow, BUT we know that exhaust flows in pulses, so you could probably get away with 3.75" tubing, but it won't be optimum. Your big problem is going to be finding any 2.75" or 3.75" tubing pieces. If you neck the pipes up to 3", there's a 3" to 4" collector for $65 from Flowmaster. I don't think you'll find cheap solutions when you're dealing with 4" diameter stuff.

Flowmaster Y300400 Flowmaster Scavenger Series Y Collectors | Summit Racing

Free Shipping - Flowmaster Scavenger Series Y Collectors with qualifying orders of $109. Shop Exhaust Pipes, Y-Pipes at Summit Racing.

www.summitracing.com

My Express is dual 3" to single 4" but that was merely because thats what it was to the muffler factory and the muffler and tailpipe I found in Summits scratch and dent area for a GMT800 just happened to fit.

Dual 3" to single 3.5" merge Ys exist and will not be a restriction even on a mild 454.

 

[Schurkey]

My plow-truck '97 7.4L needed muffler/tailpipe when I bought it. As this is mainly a low-rpm snow pusher, I found a used OEM stainless single-in, single-out muffler and tailpipe from an earlier GMT400; and adapted it behind the twin cat converters with an aftermarket 2-into-1.

I had no fun welding it in place, as the aftermarket "Y" was 3" inlet, compared to the OEM pipes being 2.75-ish.

$20 in 2017. More than that, now. Woof.

www.amazon.com/gp/product/B000COTCL2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1