Will 340 exhaust system fit 318 (1971 Duster)

[Ken71Twister]

My 71 Duster is being restored and I want to buy a full dual exhaust system that will match up to the OEM exhaust manifold. I’m currently looking at a stainless steel system at Waldron’s muffler. The OEM 318 was not available (according to employee at Waldron’s) with dual exhaust - so the company has no dual exhaust that is guaranteed to fit my OEM 318 engine/vehicle. FYI - the car has a 3-speed standard on the floor. Can anyone tell me if the OEM exhaust system for a 1971 340 Duster would match up to my 1971 318 exhaust manifold?

 

[toolmanmike]

Probably not. Check out TTI. They should have systems that fit your car and you can tell them what manifolds you are running and they provide the correct lead pipes to make it all work. Not cheap.

 

[ragtopfury]

You would need 71 340 manifolds for the 340 exhaust to bolt up directly.

 

[VOETOM]

No fit but you can get the whole 340 system, and have a local shop make the first couple of feet to fit the 318 then they can easily adapt it to the 340 system since the pipes will be in the right place.

 

[Ken71Twister]

Thanks. The guy doing the work told me to press ahead with the 340 dual exhaust system and he would make the necessary adjustments to match it to my manifold.

 

[VOETOM]

If he has HUTH or Ben Person bender, he will have cards that will give him the angles and lengths he needs. Driver's side is tricky but pass. side is easy.

 

[Ron_M]

FWIW I added the 68-70 340 manifolds and the TTI kit to my dad's 70 318. All bolt in. One of the best upgrades that we did.

 

[str12-340]

call Accurate limited and have the casting numbers for your 318 manifolds with you.

 

[RustyRatRod]

I would run the 340 manifolds. There's no down side. I would say cost, but you're talking about Waldron's exhaust so some decent 340 manifolds should be a drop in the bucket.

 

[66fs]

Passenger side is easy, any 360 came with them, 3418623 and other 360 center dump passenger side manifolds from any body style (including trucks) should also work. The drivers side any 340/360 from 68 thru 74, 2863553 or 3614368.

 

[lemondana]

340 manifolds on a 318 have the potential for a pretty good exhaust leak. I believe these days that TTI is cheaper than Accurate, and you get nice mandrel bent 2 1/2 pipes which you don't with Accurate. Give them your manifold casting numbers and they do the rest

 

[VOETOM]

I remembered a few more things. You'll need the muffler hanger support bracket for the pass. side and any of the support hangers for both tailpipes and/or tips.

 

[lemondana]

TTI systems come with all of the hangers.

 

[VOETOM]

Not sure they supply the bracket that bolts to the body that their hangers attach to do they?

 

[1971 CY Dodge Dart]

Just go TTI. Cheaper with better performance.

 

[str12-340]

340 manifolds on a 318 have the potential for a pretty good exhaust leak

I have been running 340 manifolds on both my 318 Darts for over thirty years, one with stock 1970 heads, the other with 302 heads - no leaks, no issues, no muss, no fuss.

 

[66fs]

I remembered a few more things. You'll need the muffler hanger support bracket for the pass. side and any of the support hangers for both tailpipes and/or tips.

Hanger brackets depend on pipe OD.

Exhaust - Exhaust Hangers - 66-70 B Body GTX Road Runner 2 Strap Muffler Hangers - 66-70, B, Body, GTX, Road, Runner, 2, Strap, Muffler, Hangers

66 - 70 Road Runner, GTX, Coronet, Super Bee, Charger double strap muffler hangers. Includes 2 straps. We also sell single strap hangers.

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Exhaust - Exhaust Hangers - 67-76 Mopar A Body Dart Duster Floor Exhaust Hanger Bracket - 67-76, Mopar, A, Body, Dart, Duster, Floor, Exhaust, Hanger, Bracket

67-76 Mopar A Body Dart Duster Floor Exhaust Hanger Bracket. For dual exhaust cars to mount the left side exhaust hanger. This bracket bolts to the driver’s side floor pan behind the rear seat. Original on dual exhaust cars. There are dimples marking the bolt locations behind the rear seat...

www.hooverautoparts.com

 

[Johnny Dart]

HiPo 340 manifolds on a 70 318 Dart. Dual exhaust to the back, with H-pipe. Works excellent.

Having said that. If you want to stick with your 318 logs, Accurate Exhaust, or TTi has complete systems for your needs.

 

[RustyRatRod]

340 manifolds on a 318 have the potential for a pretty good exhaust leak. I believe these days that TTI is cheaper than Accurate, and you get nice mandrel bent 2 1/2 pipes which you don't with Accurate. Give them your manifold casting numbers and they do the rest

Aren't there a couple of companies now that make some copper gaskets that'll make it happen? SCE gaskets maybe? Heck I caint remember.

 

[Johnny Dart]

Aren't there a couple of companies now that make some copper gaskets that'll make it happen? SCE gaskets maybe? Heck I caint remember.

Fel-Pro MS90460 ....... No muss no fuss.

 

[RustyRatRod]

Fel-Pro MS90460 ....... No muss no fuss.

View attachment 1716386865

Yeah. Thanks. I thought I remembered somebody made somethin that would make it happen.

 

[str12-340]

pay attention to how the 302 holes below the ports are plugged. May interfere with the older 318 or 340 manifolds if the plugs stick out far - nothing an angle grinder can't fix.

 

[CRUZE 418]

Interesting, when I tried a 340 exhaust gasket on my 318, the exhaust ports were too tall, or rather long at the bottom. Would have had a massive exhaust leak. I had to go back to 273/318 gaskets. Not sure how you can install 340 manifolds on a 318 and not have leaks. Boy, I am confused here, what changed?

 

[Johnny Dart]

Just got to get the correct gaskets.
I have proof it works with pics above.
Little teen would burn rubber all the way down the street.

 

[CRUZE 418]

So happens, that is the gasket that I was going to use. Wish that you lived around the corner to show me in person where I went wrong. Actually, wish that I had taken a picture. Maybe it's my eyes.