Exh manifolds in an Early A...

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66jim said:
Only type (Tri Y) being made I know of are old Spitfire design made years ago by
an guy named Harold in his back yard. Now Laysons is making them I believe
they are 4-5 hundred bucks? Sometimes posters have said there are discounts
available for Dougs headers thru Auto Zone I think. Anyhow Dougs are very nice.
They will cost a bit more as they are better than the Laysons.
Click to expand...

You and I have a very different definition of "cheap" :)
 
Cuda416 said:
You and I have a very different definition of "cheap" :)
Click to expand...
Yes 4-5 hundred is not really cheap to most, keep eyes open for a used set early A
headers although not too common. My point was not to waste money on other sets
of manifolds which offer little benefits.
 
66jim said:
Yes 4-5 hundred is not really cheap to most, keep eyes open for a used set early A
headers although not too common. My point was not to waste money on other sets
of manifolds which offer little benefits.
Click to expand...

Hah, fair enough, though if I can get some decent ROI with better manifolds, I'm good with that. Not looking to win races and I'd rather do the exhaust once (ish). Thanks


-=C
 
I thing I forgot to tell you about the 273 manifolds..... the exhaust port shape is much smaller than the magnum and/or the 340. You might end up with an exhaust leak if you're not careful.
 
273 ports are not as small as you think. Run the early 273 manifolds. No difference between 318 and 273 manifolds or heads. Run what fits the car and save for headers.
 
The 273 and 318 have smaller ports. Attached you can see a 318 gasket (blue one) behind a 360 magnum/340 gasket. You can clearly see daylight around the corner edges. But some FABO members have managed to get the 318 gasket to seal on a magnum/340 manifold. I swapped out my '69 318 heads for some swirl port heads to make sure that I got a good seal and to get the flow that comes with the magnum heads/ports.
DSC01769.JPG
DSC01770.JPG
 
If you look at the ports, X heads are big. You have to port the X heads to match the exhaust gasket openings. As the years went on, the ports shrunk on 360 and 318 heads. The exhaust ports are not big on magnums. I ported my original exhaust manifolds on the 64 Barracuda to seal J heads. You probably wouldn't have to port the early exhaust manifolds for Magnum exhaust ports. Don't make me take pictures...
 
I have used early A 273 manifolds on a 318 before with leaks. Both heads and manifolds were checked for straightness. No idea “why” they leaked. I switched from the 318 small port gaskets from FelPro (metal clad) to a 3/32” cut gasket white in color made for the 273 port thru Jegs. I do t remember the brand but they were an asbestos like product (high temp) and that solved the problem. I even used the proper mounting hardware (con washers, studs and proper nuts) any how Jegs sells the proper port sized gaskets. Not a fan of the Felpros anymore. Really poor quality.
 
We put Magnum manifolds from a 5.9 Durango on my son's 65 with minor mods, on a 318 and now on his stroked 360LA. Had to cut the collar thing back on the steering column, shim the left motor mount up about 1/4 inch, and because a friend of mine is a machinist, I had him shave 1/8 inch off the mounting surface of both manifolds.
 
@Treblig I haven't looked through all of your extensive post history on the magnum manifolds but I did read that ones in which you said the 96-98 JGC drivers side manifold won't work because of the inward turn towards the starter, which isn't a problem on the JGC since the starter is on the other side. My question, and maybe it was answered, is was that with the standard lunker or a mini-starter? In simple terms, might it work, or be made to work, with a mini?
 
Cuda416 said:
@Treblig I haven't looked through all of your extensive post history on the magnum manifolds but I did read that ones in which you said the 96-98 JGC drivers side manifold won't work because of the inward turn towards the starter, which isn't a problem on the JGC since the starter is on the other side. My question, and maybe it was answered, is was that with the standard lunker or a mini-starter? In simple terms, might it work, or be made to work, with a mini?
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If it could/would work I would have been machining and selling right now.........but I don't think there's any way it can be done. I actually tried to install a JGC on my '69 Barracuda (318). The exhaust outlet actually hits against the starter before you can even get a bolt into the head. It doesn't just get close to the starter it runs directly into the top of the starter. I had a mini in my car at the time so I can say with confidence that it can't be made to work. Spend the better part of a day trying to get it to fit but there was no way. The passenger's side on the other had was "made" for the A bodies!!!!!
 
Here is a side by side comparison of a 273 casting #920 exhaust port with 318 gasket and a Magnum exhaust port with the same gasket for comparison.

Magnum and 920 Exhaust Port 5.JPG


Magnum and 920 Exhaust Port 6.JPG
 
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