What exhaust manifold casting numbers should I be looking our for to fit a 318 in my 66 dart gt?

[Jcon82]

Hi All,

I've been trying to find cast manifolds (dont want to mess with headers yet) for my dart. I dont have an engine yet but it most likely is going to be a 318. Are all 318 LA heads created equal in regards to manifolds or should I wait until I have an engine on hand? I've found a few on the classifieds here but all of them are from 70's darts and I', insure if they'll fit. I don't mind taking a grinder to anything but it would be best to avoid it.

 

[Professor Fate]

There's a couple of possibilities, depending on a few factors.
1.) Do you have power steering?
If you do, you have 1 option: '64-'66 A body 273 manifolds.
If you have manual steering, later A body manifolds will also fit. Magnum manifolds can also be made to fit, but will take a bit more work.
2.) What year are the heads on your 318?
Although all the exhaust port shapes are similar, the area around the ports changed in '74 or so
from this:

to this:

This later configuration causes interference with the early manifold's outlet, which can be addressed by using a header flange as a spacer between the head and manifold. You may be able to get away with a thick or double gasket, but only trial and error will tell you for sure. Whatever you do, don't assume you can just grind the head- there's a coolant passage there.

Later manifolds do not have this interference.
3.) All fitment issues will be on the driver's side. There's no issue with any manifold on any head on the passenger side.
4.) Later heads with air injection ports need to have all those ports plugged to avoid exhaust leaks- just tap them to 1/4-20 and locktite some allen screws in there just below the surface.

 

[Jcon82]

There's a couple of possibilities, depending on a few factors.
1.) Do you have power steering?
If you do, you have 1 option: '64-'66 A body 273 manifolds.
If you have manual steering, later A body manifolds will also fit. Magnum manifolds can also be made to fit, but will take a bit more work.
2.) What year are the heads on your 318?
Although all the exhaust port shapes are similar, the area around the ports changed in '74 or so
from this:
View attachment 1716388223
to this:
View attachment 1716388224
This later configuration causes interference with the early manifold's outlet, which can be addressed by using a header flange as a spacer between the head and manifold. You may be able to get away with a thick or double gasket, but only trial and error will tell you for sure. Whatever you do, don't assume you can just grind the head- there's a coolant passage there.
View attachment 1716388229
Later manifolds do not have this interference.
3.) All fitment issues will be on the driver's side. There's no issue with any manifold on any head on the passenger side.
4.) Later heads with air injection ports need to have all those ports plugged to avoid exhaust leaks- just tap them to 1/4-20 and locktite some allen screws in there just below the surface.
View attachment 1716388232

Thanks for the details.

It has power steering and I’d like to keep it.

I haven’t settled on an engine yet. But chances are it’ll be the one I mentioned since it’s in a local wrecking yard.

Im wondering if I should just be looking into headers at this point. The car isn’t perfect so fender well headers are an option too.

 

[66fs]

I'd just run the 64-66 exhaust manifolds for the 273 and be done. You can also run the 2 1/2 "Charger" single exhaust.

LH casting# 2465847

RH casting# 2465769