318 exhaust port differences

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KENTON

KENTON

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I gave my granddaughter a /6 74 Duster I had sitting around. I also had a 75 Dodge Dart 4dr with a 318, so she put the 318 in the duster. She wanted headers so she ordered a set of Jeg's 30080 headers. When she went to put them on, the ports were so small the gasket went below the port. So much so it would not have sealed. Just wondering if anyone has some ideas she might try to fix this? Keeping in mind she is just 16 and has limited funds. The headers and gaskets are 1.8 tall and 1.3 wide. The heads are 1.4 tall and 1' wide. In the top picture you can see light showing threw on the bottom left corner. She still has the stock manifolds, but is kinda bummed she can't use the headers.
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Oh! Yea those are 340-360 ports. Just buy her one of those and the headers will fit.:rofl:

honestly those gaskets will work but find the proper sized 273-318 header gaskets if you really want to be safe. Jegs and Summit have them. Last set I bought from mr gasket like $20
 
I think the gaskets are key. They are touting the fit Ed heads, etc. Perhaps a more "generic" for lack of better set might fit "smaller." I had Hedmans on a ?70? 318 and don't even know what gaskets.......bolted 'em on forgot 'em

If I had to guess I'd say these were they

DODGE Hedman Hedders 27970 Hedman Header Gaskets | Summit Racing

Maybe you can call Summit and get lucky on a guy who can read a ruler
 
On a side note I've never known anybody that had a car "laying around" LOL and you must have an awesome grandaughter. "Something did right"
 
So here we go early 318 heads without the smog ports don't have extended Port flanges below so you end up with an exhaust leak with your typical a set of headers. The answer to this is specifically a set of Hooker Headers...they actually have is slightly shorter port aka raised port floor that actually seals up on early 318 heads. Aside from that either have to use later 318 head with your generic 360 headers...or weld up the bottoms of the port flange to seal.
If you run a real thick gasket you can get away with a little bit of protruding weld bead.
 
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67Dart273 said:
On a side note I've never known anybody that had a car "laying around" LOL and you must have an awesome grandaughter. "Something did right"
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I gave my Grandson 2 64 Sport Furys that he should be able to make one good one from. Gave my 2nd oldest Granddaughter a 64 Belvedere 4 door it was a decent 318 poly car. I only have pictures of the Belvedere. My hope is they have a love for cars like I do. Probably keeped me out of a lot of trouble. I have 2 more Grandkids that will probably get some project cars too.
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MOPAROFFICIAL said:
So here we go early 318 heads without the smog ports don't have extended Port flanges below so you end up with an exhaust leak with your typical a set of headers. The answer to this is specifically a set of Hooker Headers...they actually have is slightly shorter port erased Port floor that actually seals up on early 318 heads. Aside from that either have to use later 318 head with your generic 360 headers...or weld up the bottoms of the port flange to seal.
If you run a real thick gasket you can get away with a little bit of protruding weld bead.
Click to expand...

Thank you for this reply. We will have to decide what to do about this. We may put the stock exhaust manifolds on for now, untill she can get a 360 with better heads. Here we are Putting the wiring under the hood.
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Put them on ita all good...trust me
 
Those of you saying the port mismatch doesn't matter need to look at the picture of the gasket on the head a LOT better. There's no way that's gonna seal across the bottom of that port. Ain't happenin.
 
"A" body street car. I'd use the manifolds. Headers on these cars can be a PITA. Just my 2 cents.
 
RustyRatRod said:
Those of you saying the port mismatch doesn't matter need to look at the picture of the gasket on the head a LOT better. There's no way that's gonna seal across the bottom of that port. Ain't happenin.
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Yes, that will leak. I didn’t even see that. Well, that sucks.
 
KENTON said:
I gave my granddaughter a /6 74 Duster I had sitting around. I also had a 75 Dodge Dart 4dr with a 318, so she put the 318 in the duster. She wanted headers so she ordered a set of Jeg's 30080 headers. When she went to put them on, the ports were so small the gasket went below the port. So much so it would not have sealed. Just wondering if anyone has some ideas she might try to fix this? Keeping in mind she is just 16 and has limited funds. The headers and gaskets are 1.8 tall and 1.3 wide. The heads are 1.4 tall and 1' wide. In the top picture you can see light showing threw on the bottom left corner. She still has the stock manifolds, but is kinda bummed she can't use the headers.View attachment 1715774231 View attachment 1715774232 View attachment 1715774233 View attachment 1715774234 View attachment 1715774235
Click to expand...

Here you go. Let your grand daughter slap these on it. Yeah, the center ports are open, but big whoop, won't hurt a thing. If you look at the end gaskets, I believe they have the raised floor you need to seal those. I think they will work just fine.

1974 PLYMOUTH DUSTER Fel-Pro MS9939 Fel-Pro Exhaust Manifold Gaskets | Summit Racing
 
RustyRatRod said:
Those of you saying the port mismatch doesn't matter need to look at the picture of the gasket on the head a LOT better. There's no way that's gonna seal across the bottom of that port. Ain't happenin.
Click to expand...
People don't always read all the responses sometimes.. or it's selective reading.lol
Learned this 20 yrs ago on a 68 barracuda 318 car in ridgecrest ca. Was up there gettin a slant head worked on at krams auto machine, big valve install. My friend had tried 2 diff headers, hedman... then hooker. Hookers were the ones that sealed up properly. Hedmans and others based on those are nice n big.. for a hogged out 360 exh port that is..but dont seal like they should on a early 273/318.
Now if OP spent extra ..he could get Doug's that would have the correct small port window flange and also solve the problem.
$234 vs $600+
 
KENTON said:
I gave my granddaughter a /6 74 Duster I had sitting around. I also had a 75 Dodge Dart 4dr with a 318, so she put the 318 in the duster. She wanted headers so she ordered a set of Jeg's 30080 headers. When she went to put them on, the ports were so small the gasket went below the port. So much so it would not have sealed. Just wondering if anyone has some ideas she might try to fix this? Keeping in mind she is just 16 and has limited funds. The headers and gaskets are 1.8 tall and 1.3 wide. The heads are 1.4 tall and 1' wide. In the top picture you can see light showing threw on the bottom left corner. She still has the stock manifolds, but is kinda bummed she can't use the headers.View attachment 1715774231 View attachment 1715774232 View attachment 1715774233 View attachment 1715774234 View attachment 1715774235
Click to expand...


i ported my exhaust ports to some what match the port size on my headers and gaskets
 
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