Exhaust leak

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Romulo Roderiques

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Hello y'all. I have a 65 Dart and need some advice. My exhaust manifolds leak even after I replaced the gaskets. I removed them and installed some shorty headers I had for a 318 and the driver's side hits the gear box. I'm having a hard time finding new exhaust manifolds or headers that will fit. The car is lowered about 3 inches so I'm afraid long tubes will have no clearance. I would be ok with re-using the factory manifolds but still need to see how warped they are. Any input is appreciated.

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Set the manifold in question on a nice flat surface such as a table saw table, a piece of glass or anything else that would be true. Measure any gap with a feeler gauge to determine how far it is out. If not super bad, a machine shop should be able to grind it true, still maintaining the installation geometry.
 
CFD244 said:
Set the manifold in question on a nice flat surface such as a table saw table, a piece of glass or anything else that would be true. Measure any gap with a feeler gauge to determine how far it is out. If not super bad, a machine shop should be able to grind it true, still maintaining the installation geometry.
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Thank you
 
Yes the table saw thing ^^^.

Glue down some 80 grit long and skinny sand paper to the table saw deck. Back and forth by hand on the exhaust manifold 4 ports at the same time.

The first few strokes will mark the manifolds and show the low spots. Then keep at it until they come up straight.
 
That's going to be really hard to do with an early A manifold- the downleg is going to interfere with flat sanding the surfaces... passenger side would be okay, but not the driver's side.
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A machine shop can do it, but they'll groan when they see the setup needed.
OP did not mention where the exhaust leak is, pass. or driver's side.
It would also be good to know what his setup is- particularly the heads. If they are later model heads with the extended exhaust port surfaces (for air injection ports, even if they're not drilled for them), these "pads" will not allow the early A manifold to seat properly; the downleg hits the bottom of the port surface on #7 exhaust port. Massive exhaust leak; or worse, a cracked manifold if you try to over tighten it.
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DON'T grind for clearance! There's a water jacket just beneath the surface- it doesn't take much material removal to break through. I know, I trashed a good fresh head this way, and I removed VERY little material. Some have gotten away with it, but is it worth the chance? Best bet in this case is to double up on the exhaust gasket to space it out a bit to gain clearance, or to run a header flange between the manifold and the head.
As far as making those shorties work, they require a relatively aggressive mod to make them fit early As, as shown in this thread:
Removing stock exhaust manifolds | For A Bodies Only Mopar Forum
 
Professor Fate said:
That's going to be really hard to do with an early A manifold- the downleg is going to interfere with flat sanding the surfaces... passenger side would be okay, but not the driver's side.
View attachment 1715843194
A machine shop can do it, but they'll groan when they see the setup needed.
OP did not mention where the exhaust leak is, pass. or driver's side.
It would also be good to know what his setup is- particularly the heads. If they are later model heads with the extended exhaust port surfaces (for air injection ports, even if they're not drilled for them), these "pads" will not allow the early A manifold to seat properly; the downleg hits the bottom of the port surface on #7 exhaust port. Massive exhaust leak; or worse, a cracked manifold if you try to over tighten it.
View attachment 1715843187
DON'T grind for clearance! There's a water jacket just beneath the surface- it doesn't take much material removal to break through. I know, I trashed a good fresh head this way, and I removed VERY little material. Some have gotten away with it, but is it worth the chance? Best bet in this case is to double up on the exhaust gasket to space it out a bit to gain clearance, or to run a header flange between the manifold and the head.
As far as making those shorties work, they require a relatively aggressive mod to make them fit early As, as shown in this thread:
Removing stock exhaust manifolds | For A Bodies Only Mopar Forum
Click to expand...

Thanks. Early heads on the 273. I pulled up the old thread on what was done on the drivers side header. Looks like flange was caved in to make it fit.
 
Sort of- the #1 exhaust tube was rerouted into the #5 tube, and #1's spot in the collector was eliminated, making room there.
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They usually leak on the Dual center ports. Blowing out the bottom of the gasket area.

Passenger Side is the weaker manifold most likely to warp.

Just look at how the 2 sides are built. Driver's Side has the beef in the right areas compared to the pass where the exhaust Port flanges are standing up out in the open.
 
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George Jets said:
They usually leak on the Dual center ports. Blowing out the bottom of the gasket area.

Passenger Side is the weaker manifold most likely to warp.

Just look at how the 2 sides are built. Driver's Side has the beef in the right areas compared to the pass where the exhaust Port flanges are standing up out in the open.
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What do you recommend?
 
Romulo Roderiques said:
What do you recommend?
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Resurface that passenger side exhaust manifold. Then put the new good exhaust manifold gaskets on and put it together and run it.

You can sand it flat on your table saw deck or take it to your machinist and they can easily cut if straight for you.

Driver's side will be fine.
 
George Jets said:
Resurface that passenger side exhaust manifold. Then put the new good exhaust manifold gaskets on and put it together and run it.

You can sand it flat on your table saw deck or take it to your machinist and they can easily cut if straight for you.

Driver's side will be fine.
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Sounds like the easiest cheapest way. What do you think about using the one piece header gaskets I got for the manifolds in lieu of the the piece stock ones?
 
Romulo Roderiques said:
Sounds like the easiest cheapest way. What do you think about using the one piece header gaskets I got for the manifolds in lieu of the the piece stock ones?
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One piece header gaskets will work fine with the stock manifolds. They will seal better than the Stock Style gaskets .
 
That driver's side header looks close to fitting. Do you think a shim under the motor mount on that side could make it happen?
 
RustyRatRod said:
That driver's side header looks close to fitting. Do you think a shim under the motor mount on that side could make it happen?
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It fits with the engine jacked up about 2 inches. The only way around is to modify that header like the other guy did. Or go back to stock manifolds. For me anyway.
 
I do have another question though. Isn't there like a donut type gasket that goes here? If so where can I get some?
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Romulo Roderiques said:
I do have another question though. Isn't there like a donut type gasket that goes here? If so where can I get some?
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That is a bell fitting, just clean the rust off with a wire brush. Paint on a little Anti-Seize to the bell and bolt on the bell flared end of the Exhaust pipe, with it's slide on flange.

Just like this picture, no exhaust doughnuts or flat gaskets to blow out. Mates up nice to whatever angle the exhaust pipe comes in at.

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Truck manifold pictured here, but same application.
 
No doughnut, the pipe is flared with a flange that seals it.
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If the "bell" is too corroded to give a good seal, a little exhaust cement on the mating surfaces will seal it up.
 
Romulo Roderiques said:
It fits with the engine jacked up about 2 inches. The only way around is to modify that header like the other guy did. Or go back to stock manifolds. For me anyway.
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I see. Well, if you're decent with a welder, I think I'd relocate me a header tube. lol
 
I found a local fabricator to modify that header and also fab up a mandrel pipe. Will I still need a mini starter? If so, what is the best place to find one that will fit my Dart?
 
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