building new duster exhaust

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jamesdart

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i cut off the factory pea shooter exhaust today, if we get lucky with the weather during the week ill build the new 2.5" system. factory system had a muffler and resonator. i got curious and cut open the resonator as it really wasnt that quiet even with the new muffler it had on it. there was nothing in the resonator, a straight through tube in it that had about 6" of preforation. i expected to see some sort of packing. maybe ill post some pics when done. im using a dynomax super turbo and a louvered glasspack as a resonator. wifes car and she asked me to keep it quiet. its a stock 225 with the super six added, manifold gasket matched and outlet opened up. im using 2 1/2 because i had a lot of left over parts from my 69.
 
thats cool. i had 2 1/2 stuff lying around so i went with it. if i decided to step things up the exhaust will be good to go. if 2 1/4 was stock on the super six, 2 1/2" wont hurt. especially in a lighter car, something as simple as a carb swap will like more flow. exhuast shops around here stink so i learned a long time ago to build my own systems. every shop i walked into when i was 17 to get an exhaust done claime they had to step down to get over the rear axle. as if the wrinkle bends arent bad enough. anyway i built the system today after work.
 
everyone says 2 1/4 was stock for the super six? ill let you all know how it works. mandrel bent front to back, for about 100 bucks.
 
the car
IMG_1666.jpg


the headpipe
dusterheadpipe.jpg


the tailpipe with glasspack resonator
dustertailpipe.jpg


i cut a new flange for the headpipe out of 1/2" plate. 14" dynomax super turbo muffler, i ran it with just the muffler and it sounded like a 13 second car, which is cool, but its far from a 13 sec car so im glad i used the resonator. there is a turndown right at the bumper ill have to get a pic installed tomorrow. i have fun building exhausts i built 2 for my 69 both with home made x pipes. one 3" with flowtech terminators the other 2 1/2" with ultra flows, built an H pipe 2 1/2" system with 2 chamaber flowmasters for my brothers barracuda, a 2 1/2" system with real long thrush turbos for a 67 impala my dad and i were working on, 2" with a thrush glasspack for my 31 essex, and a 3" system for a 78 nova that my buddy has and a few truck systems. i have played with all kinds of mufflers in sizes from 2" to 3.5" on cars and trucks, they all have thier purpose. there is no single best muffler or pipe size for every application.
 
My 73 didn't have a resonator on the exhaust. I installed a PowerPipe (enlarged exhaust manifold, in essence) and a 2¼ pipes from front to rear. Lacking your welding and tube bending skills, I farmed out the exhaust pipe, used the cheapest "turbo" muffler I could get, and used a LH 2¼ inch V-8 tail pipe. It's nearly silent at a steady state cruise but sounds very pleasant under light acceleration or idle. The sound is not much different from stock except it is at a significantly lower pitch.
 
i dont know what the deal was with the resonator, i think its the only a body ive ever seen with one. it was definitely a factory piece though. so just like i read, i didnt notice any power difference when i swapped to the super six and kept the stock pipe, but its nite and day now with the 2 1/2". its no rocket ship but it moves pretty damn good for a six. im thinking it would be fun with some 3.55s.
 
Hey Rug
When i went to 2 1/4 I just mounted the exhaust flange to the manifold flange and went to the muffler with 2/1/4 then out with 2". Works great.
Frank
 
Very nice work for sure. I did mine with 2.25" pipe, a reproduction 340 muffler and tailpipe going into a stainless tip.
 
you are right the outlet of the manifold is not 2 1/4, but a stock super six exhaust IS. i cut the head pipe off the volare wagon. leaving that lone will leave an existing restriction never mind anti reversion. open it up and let the engine breathe. there is plenty of meat there to open it up to 2 1/4 with no issues. 20 min with a burr and a die grinder. like swapping from exhaust manifolds to headers, i dont think there is a car out there that doesnt like headers. i am sure 2" and 2 1/4" works but without back to back testing who really knows what is best.
 
Ok lets make sure everyone is on the same page. The exhaust Manifolds are ALL the same size (the only real differiance is the choke pocket) the Head pipe is the start of the exhaust tubing headed under the car. This WAS different for the super six and was sized at 2 1/4". The factory ran 2 1/4 from there to the muffler, then 2" from the muffler out.
Frank
 
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