The Stovebolt Site Forums The Shop Area Engine Shop 2 into 1 exhaust?

What is the advantage of running your 2 exhaust pipes from the header into 1 pipe?

Quiter? Cheaper?

I know alot of newer manufacturers take 2 into the catylitic converter, and 1 or 2 out. This generates more heat and aids the converter in doing its job more efficiently, but this doesn't apply to old trucks.

Oh yeah... 302 gmc 6 with fenton dual exhaust in 1940 gmc 3/4 ton.

The only advantage I would see is clearance problems.

I figger this has to be economics. Single exhaust has been the "standard" since times were better. One tailpipe, one muffler, etc. Costs less to produce and less to maintain. Dual exhaust was almost always an option, unless it was part of the performance package as in the case of the Olds 442 (4-barrel, 4 speed, dual exhaust.)

Long ago I was told that the best thing I could do to improve the performance of a Chevy V8 was to get rid of the "strangulation" single exhaust and add headers and duals. I dunno how much truth there is to it, but that was the conventional wisdom of the day (a long time ago.)

I've read that the performance advantage from dual manifolds/split manifolds is maximized after about 3 feet of pipe- after that two pipes/two mufflers are for looks and sound. If you want two pipes you should 'x' them at the cross member. If not, 'y' them at the cross member.

Anybody know +- on a 2 in, 2 out muffler?

Well... a plus is that it sounds SO good Of course since I have one I just may be biased.

Thanks for your help. Read about this setup in a couple of posts

Dennis M, I have a 2 in 2 out muffler on my '32 bolt. I made it myself when I worked at a muffler shop many years ago. Jaguars had a similar muffler on the 6 cyl. cars, also I have seen a 2 in 2 out muffler advertised in some of the street rod magazines. It makes a unique sound still the split 6 rap but subdued. I think mine sounds great.

I did twin 2" from the Fenton to under the cab where I used a single 2.5" inlet muffler with twin 2" outlets. A stock muffler was used to subdue the noise to what I consider respectful. I don't know how this would compare to a 2x2 setup but it sounds great (to me) and looks terrific with the twin chrome tips and was inexpensive. I looked into the 2x2 setup but was unable to find a muffler that was the proper size and shape but am delighted at how it all turned out regardless. This truck is for my wife who likes the sound a bit quiter than I might prefer but it is still OK. The worst part was making the two into one pipe ahead of the muffler.

Flowmaster makes a flat 2 in 2 out muffler and dynaflow makes a round one that looks like the factory muffler in the truck.

The dynaflows are more like 2x2 glass packs, and in my opinion (no offense intended to anyone...) sound like a rice burner auditioning for fast n' furious.