Different Exhaust Manifolds Needed for Dual Exhaust?

[Henrius]

Previously I posted a question on whether to convert my 1972 Newport Custom 4 door hardtop with 400 cu. in. engine to dual exhaust. You guys convinced me to do it.

So I e-mailed my favorite exhaust part fabricator, Waldron's exhaust. Here is their reply:

"In 1972 Chrysler did offer these vehicles in either a single exhaust or a dual exhaust. We do not know what must be done when changing from a single exhaust to a dual exhaust system. We do know that there are definitely years when you must change out the driver side manifolds in order to change from single to dual exhaust. We strongly recommend that you check our a Chrysler forum and ask others what must be done. Another way is to google your exhaust manifold casting numbers. You should find sites that will tell you if the manifold is adaptable to dual exhaust. Waldron’s Exhaust will not guarantee fitment so you will want to do a bit of “homework”."

Are they being super-cautious on a conversion, or might there be a real issue here? I would hate to pay that sort of money for stainless steel duals and then not have the thing mate up to the manifold on one side.

 

[68 4spd Fury]

Chrysler, to my knowledge, only had factory dual exhaust with the HP manifolds. That said, I've never heard of an issue adding a dual system to any engine. The only issue I can think of would be interference or close contact with the starter and/or starter wiring.

 

[Big_John]

The answer is to buy a TTI exhaust. They will ask for the casting numbers on the manifolds and there ya go...

 

[FURYGT]

The answer is to buy a TTI exhaust. They will ask for the casting numbers on the manifolds and there ya go...

I agree. There are probably other companies that will ask this question. Depending on what your goal is, from a performance standpoint it is much better to switch to the HP exhaust manifolds when switching from a single to a dual exhaust system. FYI, the early 70's C Bodies used different left side exhaust manifolds for the 400/383's vs. the 440.

 

[Ross Wooldridge]

Just go to a good muffler shop and have the tech there make it with the factory bend cards. All good shops will have the cards either in their files or available on a company database.

 

[polara71]

Chrysler, to my knowledge, only had factory dual exhaust with the HP manifolds. That said, I've never heard of an issue adding a dual system to any engine. The only issue I can think of would be interference or close contact with the starter and/or starter wiring.

Negative, duals were available with non HP manifolds

 

[PontiacJim]

My '73 Fury was factory single exhaust on the 360CI. I bought the car with an installed dual exhaust set-up. The receipts with the car show that it was done at a local automotive shop. Front pipes cost $45 each on March 30, 2016. Tail pipes were $35 each and no mention of mufflers so I guess the owner supplied them. Clamps & hangers were added plus the labor/shop supplies.

I would bring it down to them to put it up on their lift to take a look to see what they would be getting into just to be sure there will be no fitment issues.

 

[rapidtrans]

Apparently duals came with a different log style manifold outlet flange. My Monaco came with the 383 4bbl, single exhaust.
TTI offers dual exhaust systems for the car but not for the manifold serial nos. on my car. Haven’t called Waldron but that sounds like a no go also.
Rather than try to piecemeal a system i’ll go the local muffler shop route. As long as they get the tailpipe turn-downs correct.

 

[LocuMob]

Apparently duals came with a different log style manifold outlet flange. My Monaco came with the 383 4bbl, single exhaust.
TTI offers dual exhaust systems for the car but not for the manifold serial nos. on my car. Haven’t called Waldron but that sounds like a no go also.
Rather than try to piecemeal a system i’ll go the local muffler shop route. As long as they get the tailpipe turn-downs correct.

What manifold numbers do you have? I was going to use a tti manifold back kit, but that would suck if it won't work.

 

[CBODY67]

The issue is that Waldron is being cautious so they don't get something back as "they're all the same" (according to some owners).

Dual exhaust C-bodies existed BEFORE the beloved HP manifolds of the later '60s. The '67 Chrysler 383 4bbl came with factory single exhaust, but similar Plymouths and Dodges got dual exhausts. Different exhaust manifolds? Kind of doubt it.

If the same year car uses different lh manifolds on the 440 than on a 383/400, it'd probably due to steering column clearance issues.

Might need to consult the particular Chrysler parts book for exhaust manifold differences, plus some OEM pictures.

When I added some OEM duals to my '80 Newport, the donor was a '79 ex-police unit. Had to get the rh manifold as the flange was clocked differently from what was on the '80. The '79 had a manual heat riser valve and the '80 had the vacuum operated valve.

If you've had good luck with Waldrons, then do the research they request. I know the quality of workmanship and materials in private shops can vary greatly, from experience. Or look for another source?

CBODY67

 

[Henrius]

Just go to a good muffler shop and have the tech there make it with the factory bend cards. All good shops will have the cards either in their files or available on a company database.

I had my heart set on an all stainless steel exhaust system, which is not available in most muffler shops. But I think I will follow your advice and compromise. I'll have Waldron fabricate the mufflers and tailpipes to spec out of stainless. Then I will go to my local independent muffler shop, which is owned by a patient of mine, and have them bend the pipes and run forward to connect to the manifolds.

The connection between the Y-pipe and the manifold frequently worked loose, blew out, and became noisy. Perhaps it will happen less often with dual exhaust.

 

[CBODY67]

Of course, all you might need to do is to cut the y-pipe several inches past the manifold connection, then put the dual pipes onto those stub-pipes.

CBODY67

 

[Ross Wooldridge]

Interesting - all the muffler shops in my area offer stainless as an option...

 

[LeBaron1973]

When I had my 78 Lincoln town coupe fitted with duals I took the car to the exhaust shop who put her on the lift. After a look I made an appointment and dropped off the car.

Great result.

May be better to have one place do everything as if yours fails then Waldron and the other shop will blame each other.