273 Exh Port MisMatch

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I told him to check the flange orientation back in post #2. all 273 early A manifolds point back...
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67s started to point down
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340's point slightly forward and have larger ports.
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You may end up getting away with just a clean up and a proper gasket orientation. It looks like you got plenty of surface there. Your post 9 pic and my post 4 pic look about the same. By opening up your port, your going to exceed the gasket profile and that will not help. Just try the (new) gasket the correct position and it should seal right up.
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RustyRatRod said:
Chit if I know man. Since you've not bothered to post a picture of the offending manifold, I don't even know why I'm trying to help. You think you might can do that? The WHOLE manifold? Then the offending port. A casting number and date code.
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Here Ya Go Rusty! I laid on my old back jus' for you man! (I couldn't read the numbers thru the Scale tho)

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pishta said:
I told him to check the flange orientation back in post #2. all 273 early A manifolds point back...
View attachment 1715811649
67s started to point down
View attachment 1715811650


340's point slightly forward and have larger ports.
View attachment 1715811651

You may end up getting away with just a clean up and a proper gasket orientation. It looks like you got plenty of surface there. Your post 9 pic and my post 4 pic look about the same. By opening up your port, your going to exceed the gasket profile and that will not help. Just try the (new) gasket the correct position and it should seal right up.
View attachment 1715811652View attachment 1715811653
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I can Re assemble with No Gaskets tho, Right? I was told that was correct/or better in some way.
 
2465857
273 1964-66 Dart & Barracuda / Left 2465857

^^ Id still give it a dab of ultra copper RTV to fill the 58 years of corrosion pits. ^^
 
That appears to be the correct mannyfold. Can you post a pic of the offending port?
 
eekvonzipper said:
Yeah, It Shows That The Flipped Gasket was the Issue...

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I'm tending to agree! @Max1196 nailed it in post #3. I also wouldn't recommend assembly without gaskets. A lot of Chryslers didn't use exhaust gaskets from the factory, but they were assembled with brand new parts with no pitting from rust or warping from heat. I would use the manifold gaskets. That said, I prefer the one piece kind, if you can find them.
 
Thanks to All for your Insane Wisdom! I just Couldn't see the obvious... Yeah @Max1196 called it right from the start!
Motor comes apart time! Wish me luck...
 
Professor Fate said:
Manifolds were never intended to use gaskets anyway,
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You really lost me here... dies "never intended to use gaskets refer to the presses metal gaskets that were original???

Another clarification: " rear firing" manifold means rear facing exit???
 
str12-340 said:
You really lost me here... dies "never intended to use gaskets refer to the presses metal gaskets that were original???

Another clarification: " rear firing" manifold means rear facing exit???
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Lost me too, because these were the original style gaskets that Mopar used on the early A 273s
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str12-340 said:
You really lost me here... dies "never intended to use gaskets refer to the presses metal gaskets that were original???
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chewy said:
Lost me too, because these were the original style gaskets that Mopar used on the early A 273s
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Okay, I should elaborate- they never used composition gaskets. The steel shims, when used, were more of a spark plug heat shield than a gasket. And they weren't used on all motors. Most of the time they went on bare. I'm pretty sure slants were the only engine that used composition gaskets on the exhaust, and that was only because it was a single gasket with the intake.
 
Those were more of a heat shield than a gasket as it was just stamped tin, no gasket crush benefit on stamped tin. Many B/RB didnt get exhaust gaskets, cant comment on LA's as I never had one apart that was so original as to have the factory 'no gasket'. "rear firing" was just a phrase I used to denote a stock 65 driver side exhaust manifold as they all had that flange position. laters ones and 340 (possible here before we found the flipped gasket) never had a rear facing flange. Who new what the prior owner had on that as they get swapped out so often.
 
Very interesting. I never read that many factory engines had no exhaust manifold gaskets. Every one I've taken off had a gasket, but someone might have been "in there" before me.

Is it true that we don't need those metal heat shields now that spark plug boots and wires are silicone instead of the older rubber (nitrile, i.e. Buna-N?). On my 1965 383 engine, the heat shields are secured under the outer head bolts and get in the way when pulling off the plug wires. My 1965 273 doesn't have heat shields and I don't have any old ones.
 
do a good job of routing modern material wires and you are golden. A lot of small blocks (at least mid 60s to early 70s) had good looms made into the valve covers and all of them have the plastic insulators available new.

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str12-340 said:
You really lost me here... dies "never intended to use gaskets refer to the presses metal gaskets that were original???

Another clarification: " rear firing" manifold means rear facing exit???
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He's talking about "some", but not all. Some of the small blocks through the 70s never used exhaust manifold gaskets. They used the flat machined surfaces to seal.
 
str12-340 said:
do a good job of routing modern material wires and you are golden. A lot of small blocks (at least mid 60s to early 70s) had good looms made into the valve covers and all of them have the plastic insulators available new.

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I used some 318 Valve Covers on mine So I could have a More Modern PCV System and the Plug Wire Routing was a Bonus.
I didn't care for the StovePipe Covers I had... They sold in a bout 10minutes in here! Lol

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eekvonzipper said:
I used some 318 Valve Covers on mine So I could have a More Modern PCV System and the Plug Wire Routing was a Bonus.
I didn't care for the StovePipe Covers I had... They sold in a bout 10minutes in here! Lol

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I've never liked the early valve covers either. I don't even like the Commando cover. I know.....blasphemy, but I don't like um. Glad you found the exhaust leak was such an easy fix. That was cool.
 
RustyRatRod said:
I've never liked the early valve covers either. I don't even like the Commando cover. I know.....blasphemy, but I don't like um. Glad you found the exhaust leak was such an easy fix. That was cool.
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That's just wrong Rob. You ain't right dude!
 
RustyRatRod said:
I've never liked the early valve covers either. I don't even like the Commando cover. I know.....blasphemy, but I don't like um. Glad you found the exhaust leak was such an easy fix. That was cool.
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That Was Cool! but, It's in a thousand pieces now, getting a Freshen-up for Spring when the 4-Speed goes in.
I'll have those 3-Speed pieces for you soon, I promised you the Three-on-th-tree linkages remember?

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pishta said:
you have another option. Get a port flange like 1/8 thick and mill that portion down 1/8. Bolt that between the manifold and the head to give you another mounting surface. hit that area with a stone and get it flat so you can see where the low spots are. Ultra copper RTV works on exhaust flanges. I think you got enough to seal with only the manifold. dab some paint (zinc oxide) on a manifold and put it on and see where the paint hits.
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Pretty slick....!
 
The early 273 manifolds will hit on later heads causing #7 to leak. The long outlet hits the leveling boss on the edge of the cylinder head down by the lower right hand head bolt. This keeps the port from sealing. And cranking down on the bolts will just break the manifold. Not saying this was a factor in your situation, but it's worth checking.
 
C130 Chief said:
The early 273 manifolds will hit on later heads causing #7 to leak. The long outlet hits the leveling boss on the edge of the cylinder head down by the lower right hand head bolt. This keeps the port from sealing. And cranking down on the bolts will just break the manifold. Not saying this was a factor in your situation, but it's worth checking.
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And whatever you do, don't try to grind the extended port flange on #7 to get clearance, there's a water jacket right under the surface. I trashed a perfectly good 308 head that way. The only safe way I've found to do it is to mount a bare header flange as a spacer between the manifold and the head.
FWIW, I've run into this same type of interference with left side early 340 manifolds on Magnum heads, too.
 
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