dual exhaust on a 273

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crashcaptn

1965 Dodge Dart GT
Joined
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I'm sure it's been answered a thousand times, but what size pipes would be best for a dual exhaust system a 273? I'm guessing 2.5 inch pipes..? I also am thinking of doing basic Turbo mufflers because I'm not looking for a crazy loud sound or anything ridiculous like that, i just want that really nice toned sound at idle and a decent rumble at take off..

Any suggestions?
 
depends on how much is done to your 273...if its stock or mild i dont think I would go much over 2", maybe 2 1/4"...you do want a small amount of backpressure

I run 2.5" on my 400 hp 340
 
My 273 has headers leading into 2.5 into Flowmaster 40s and then dumped before the rear axle. The motor is bored over some with Mopar purple shaft cam, Edlebrock 500 CFM carb, Performer intake, Accel 300+ ignition but that is all. The exhaust was already installed when I bought the car and didn't like the sound it had because the pipes was ran out the back. So I removed the pipes out the back and dumped it. My friends say now it sounds as if it has a big block in it. LOL. It isn't loud and it has that nice rumble to it that you mention. I need to have a H-pipe installed or X-pipe so if you decide what to do don't forget about that. It would be good if you go the X route.
 
One of my businesses I own is a custom exhaust shop and like Sanguine says 2" would be best, but I don't install 2" on anything. 2.25" is the smallest exhaust systems I install and that is what I would go with on your car, 2.5" is way to large, you will loose some low end torque.


Chuck
 
I had a 2.25 duel system on my stock 273 and it was ok. The only problem I had was the motor couldn't keep the exhaust hot when ideling in cool weather. It would spit out black water. Not a problem in the summer time when its hot outside. Bob
 
Excellent! Thanks guys, i'll go with the 2.25 inch pipes! I have the commando 273, only difference so far is a new holly performer with the stock 4 barrel intake (a new intake will happen once i can find one). Do you think the turbos are a good choice for a muffler?
 
You might need a different trans cross member for duels if its an early a body. Not sure what years,66 and earlier? The right side needs to be clearanced for the pipe.
 
Ive heard that before. i might go to my muffler guy and ask him about what i should do.. does anyone else know about that?
 
i u were going with a 3" pipe i would say you might have problems on the exhaust due to x-memeber! on my 318 in a 65 bcuda i went with 2in duals with a balance pipe. ran it right under my x-member on both sides. can't even see it on the car!

2.25 in would be the same thing. i like the 2 in and it sounds good at the back of the car and definitely not too loud. i used generic mufflers from my muffler shop.

i toyed with idea of a 2.5 inch single. the only reason i didn't was the tightness of my not correct 75 exhaust manifolds. DS is tight, necessitating 2 inch exhaust at least until it got out of the engine bay, i just went with it all the way.
 
I'll have to watch for that then. I was also thinking of running 318 exhaust manifolds.. i dont have a set yet, but how much should i be spending on a set? and is it even a good idea? From what i see, it makes the car breath a bit better. Any thoughts on that?
 
Headers will let the car breath better. More power, torque and mileage. The down side is low hanging pipes and possibly denting them. Also gasket blow out is possible. If that problem comes up, Mr. Gasket Ultrs seals are excellent.
For a quite muffler, I used Thrush turbo mufflers. There not a hi-flowing performance muffler, but the do make a nice rumble when I hit the long pedal. Interior noise is at a min.
On my 400 cid, I went from a stock single to headers and duals @ 2-1/2 with an "H" pipe. 2-1/4 is just fine for the 273.
 
Hey Crash,
Check out my little thread in the early a-body section about the tranny mount modification. I used the TTI instructions from my exhaust kit. It was very easy to do and you will be setup for the tti's if you got that route. Or you will just have better clearance for dual exhaust from the muffler shop. It took me about 2.5 hours total time including sandblasting, grinding, welding and painting.

http://www.forabodiesonly.com/mopar/showthread.php?t=17901

-Dave
 
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