Magnum manifolds on a 66 dart

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Polara66

Polara66

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I’ve been reading/researching this for a couple of days now and so far I haven’t found a definitive answer.

What I have found is that apparently the passenger side magnum manifold fits. What I haven’t found is a definitive answer on the drivers side. Do they or don’t they?!? Has anyone used magnum manifolds on the driver side? Any pics?

I have a 340 and the car is a 904 with manual steering/brakes. I’m trying to let the 340 breathe decently without breaking the bank on headers or 68-70 340 manifolds.

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With manual steering, you stand a chance. Neither manifold choice will work with power steering. If you're using column linkage, probably not. You will need to cut back the outer column (almost to the firewall), probably eliminate the pot coupler in favor of a U joint, and possibly do a bit of clearance grinding on the manifold for column clearance. And most likely do some motor mount shimming to fine tune your clearance. It's tight, to the point that you may or may not need to do all of it- production tolerances are sketchy and what one person gets away with may not be enough for the next guy.
Even with the 340 manifolds you'd have to do most of that, anyway.
 
There are two sizes of outlets on them. 1-7/8 and 2-1/8. The latter come from trucks, vans and certain year (96ish?) Jeep Grand Cherokee. The JGC gets you the passenger side wide opening and in my case, a van got me the drivers side. The JGC drivers side won't work because the starter location for them is on the other side so the EM rides too tight to the engine. The biggest problem is the narrow engine bay. You'll likely need to shave the drives side down or shim the motor mounts. Steering column is also known to get in the way so that might need to be dealt with as well. In most cases it seems the pass side is "OK" but occasionally needs the casting numbers ground to get just that much clearance.
 
Cuda416 said:
There are two sizes of outlets on them. 1-7/8 and 2-1/8. The latter come from trucks, vans and certain year (96ish?) Jeep Grand Cherokee. The JGC gets you the passenger side wide opening and in my case, a van got me the drivers side. The JGC drivers side won't work because the starter location for them is on the other side so the EM rides too tight to the engine. The biggest problem is the narrow engine bay. You'll likely need to shave the drives side down or shim the motor mounts. Steering column is also known to get in the way so that might need to be dealt with as well. In most cases it seems the pass side is "OK" but occasionally needs the casting numbers ground to get just that much clearance.
Click to expand...
What driver’s side casting number did you use? Any pics?
 
That will need to wait until I get home and to be clear, I've not installed them yet but it's been done loads. There are several threads here about it.
 
www.forabodiesonly.com

YES 5.9 Magnum manifolds work in early A bodies. Here is exactly how!

I just finished my project of installing 5.9 magnum manifolds into my 65 dart running a 340, 904LA automatic floor shift transmission. I did a lot of research on this site, did a lot of trial and error and here is exactly what I used to make these manifolds work in my car. 5.9 magnum manifolds...
www.forabodiesonly.com www.forabodiesonly.com
 
These will never flow like headers but they do help a little.
Mopar Muscle magazine did a test on a crate 360 many years ago, comparing the HP and torque numbers using several different manifolds, then headers. The 340 manifolds added a surprisingly small power increase over the basic 318 manifolds. Headers added far more. The 340 manifolds added something under 10 HP, a number you can hardly feel.
I did my own research on this subject many years ago and figured that while every little bit helps, it becomes pointless if you are spending a lot of time and effort to get manifolds to fit because the gains are so small.
 
Kern Dog said:
These will never flow like headers but they do help a little.
Mopar Muscle magazine did a test on a crate 360 many years ago, comparing the HP and torque numbers using several different manifolds, then headers. The 340 manifolds added a surprisingly small power increase over the basic 318 manifolds. Headers added far more. The 340 manifolds added something under 10 HP, a number you can hardly feel.
I did my own research on this subject many years ago and figured that while every little bit helps, it becomes pointless if you are spending a lot of time and effort to get manifolds to fit because the gains are so small.
Click to expand...

Fair but if you're after a nice street ride, they aren't a bad option. Given the choices later A bodies have I'd easily opt for headers of any kind, but with the premium on early stuff, off... I'm a cheap *** so... lol
 
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I had magnum manifolds on my 66 Valiant before I went back to the slant. I shimmed the motor mounts about a 1/4" and it was Tight! I ended up using a u joint style coupler on the gearbox to gain some clearance.
 
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