5.9MAGNUM EXH MANIFOLDS

[Treblig]

IIRC the "large" outlet parts are 92 only.

At least on Dakotas.

That's what I remember, 92 and maybe 93 (Dakota). The only other large hole manifolds are in the 96/97/98 Jeep Grand Cherokee V8 motors. My point is that the large hole manifolds take up more space than the smaller hole ones so they aren't going to fit as easily as the ones in Krazymofugger's early A. But Krazymofugger still did a nice job of getting some larger manifolds (maybe 1 7/8" hole) into his early A!!!!!

 

[Krazymofugger]

This website has helped me in a lot of ways so I hope any of this info helps others. Thanks for the complement Treblig.

 

[subcom]

This thread inspired me to mock up my '94 2 1/8" manifolds on my 65. I believe these may have come from a van. I tried these and a smaller outlet manifold on the driver's side and the clearance issues look to be the same. They're both really close. Maybe shave an 1/8"

 

[subcom]

Pics

 

[Treblig]

You know many FABO members have loosened the steering shaft where it attaches to the firewall and managed to skoot (technical term) it over just enough to clear the manifold. Might also help to loosen the steering column a little to make it easier??

 

[Svensson]

Those were the larger ports manifolds. I installed them many years ago with some grinding at the D/S. When swapping to a 440, I sold the manifolds and the next guy had a hard time to install them on a 1966 Fish

 

[66fs]

What later small block heads have larger exhaust ports?

magnum?

340 and 360 heads have the large size exhaust ports. 273, 318, and magnums all have the smaller size exhaust ports. The "302" 318 heads have the small exhaust ports also.

 

[Treblig]

340 and 360 heads have the large size exhaust ports. 273, 318, and magnums all have the smaller size exhaust ports. The "302" 318 heads have the small exhaust ports also.

318 "302" heads have the larger ports. I put a set on my '69 318 and the ports fit the 360 gaskets exactly. My Mopar book also states that the 302 heads come with the larger ports.

 

[toolmanmike]

Magnum manifolds are on my 64 valiant wagon. They are off a 94 dodge van that the 360 came out of thats in my car. I have schumaker urethane conversion mounts. I had the manifolds machined on the mating surface . The thickness of the gaskets is all they took off. I ground off all the casting numbers so i couldn't tell you what they were its been several years ago when i did this. I also had to change the steering joint to a universal one i picked up on ebay. this set up has beenView attachment 1715410343 View attachment 1715410344 View attachment 1715410345 View attachment 1715410347 my daily driver for about 8 years now. View attachment 1715410353 View attachment 1715410352 View attachment 1715410351 View attachment 1715410350 View attachment 1715410343 View attachment 1715410344

View attachment 1715410346

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Did you remove the lower column bushing/ seal for extra clearance?

 

[66fs]

318 "302" heads have the larger ports. I put a set on my '69 318 and the ports fit the 360 gaskets exactly. My Mopar book also states that the 302 heads come with the larger ports.

Red 273 920 heads and 302 Heads

red 273 920 heads and Magnum heads

 

[Krazymofugger]

Did you remove the lower column bushing/ seal for extra clearance?

I did not it was deteriorated beyond use . I just never replaced it. i have a new one on my shelf waiting for me to do it.

 

[rdunnam]

Svensson, did you paint your manifolds with what type/brand of paint? And do I see a manifold - to- pipe gasket in one pic? I was thinking no gasket, they seal with the bell-end shapes that mate together and that was it. Let me know, thanks.

 

[Svensson]

Hi RDunnam!
Sorry for the late reply. I painted them with the VHT system. It looked nice for a while but then the colour faded like it always does... On my 1962 I had a better result with the POR15 system.

I cut the bell-ends off and made me flat flanges with 2 bolt gaskets. Worked pretty well.

Sven

 

[65MagnumFish]

This is an old thread but super interesting. So to clarify I “can” use both sided magnum logs and they will fit in my 65 barracuda with customizing? If so which years should I get after? I’m going to run a magnum 360 with eddy intake 650 Holley and stock heads and a Hughes steam roller cam. Would the logs compared to Doug’s headers be a dramatic horsepower and torque decrease?

 

[273]

Putting together a 273/4bbl, 340 spec solid cam, high compression motor for a '65 Dart. Was thinking of using the magnum factory style exhaust manifolds. Good idea? Need the magnum bolt kit or just use the LA studs/bolts?

There's not a big difference in power its up to you. Manifold and header shoot out, magnum are similar to 340 manifold performance, there another shoot out somewhere shows the best pair is one 340 and one magnum, forget which ones.

Installing Exhaust Headers Into 300hp Crate Engine - Mopar Muscle Magazine

 

[MOPAROFFICIAL]

I wonder if the summit mag shorties would fit then ,saying they hook to the factory pipes

 

[65MagnumFish]

There's not a big difference in power its up to you. Manifold and header shoot out, magnum are similar to 340 manifold performance, there another shoot out somewhere shows the best pair is one 340 and one magnum, forget which ones.

Installing Exhaust Headers Into 300hp Crate Engine - Mopar Muscle Magazine

I can’t see the full article. It seems like a good one. Just like everyone on here has mentioned long tube headers for early A cars are stupid money. I found the idea of running the magnum exhaust interesting and coincides with what a gentleman locally mentioned to me off handedly. I was going to buy the Doug’s Headers but if it’s a small difference in power it’s worth looking into.

 

[273]

I can’t see the full article. It seems like a good one. Just like everyone on here has mentioned long tube headers for early A cars are stupid money. I found the idea of running the magnum exhaust interesting and coincides with what a gentleman locally mentioned to me off handedly. I was going to buy the Doug’s Headers but if it’s a small difference in power it’s worth looking into.

On a 300hp crate 5.9l magnum, they did 318,360,340 manifolds and made 311hp, 314hp and 315hp respectively they didn't have magnum but there around 340 output.
headers they had shorty, 1 5/8, 1 3/4, tti and made 321hp, 319hp, 319hp and 327hp respectively. other than the tti there's barely any difference than the 318 manifolds and the 16 hp tti gain is debatable for the price.

 

[Dave_J]

This is (Stolen) from a forum long ago and I can not give credit to the person.

"Installing Durango/Dakota Exhaust Manifolds in an early A body

This is the unit installed in 360 66 Barracuda. They clear everything by at least 1/4" without mods. The tightest spot is directly below the center ports. Early A-Bodies are sadly neglected by the aftermarket industry so it becomes necessary to create your own exhaust system or pay nearly a $1000 dollars for a set of headers. Durango/Dakota manifolds were an inexpensive and relatively easy choice. The manifold is the same whether it was 318 (5.2) or 360 (5.9). Late 90 units through the early 2000's are best.

Surprisingly enough these exhaust manifolds will fit with some minor tweaking in any 64-66 Dart, Valiant or Barracuda without power steering. The major considerations before attempting this modification are, new collectors and exhaust will have to be fabricated due to the fact that the collectors are in different positions from the original 273 manifolds. And the clearance between the steering box and the center of the manifold will be tight. The steering shaft may contact as well. I had to trim and grind a little bit for good clearance.

The benefits are that the collector pipes can be up to 2 1/2" wide and still mate to the manifold, better exhaust flow is due to the larger "log" and no constrictive flattening of the collector around the starter. I compare the stock units to trying to "crap" through a cocktail straw.

The manifold bolt pattern is the same on any 273 through 360 engine. You will need Dakota/Durango gaskets. If you have a die grinder this would be an excellent time to gasket match your exhaust ports. The ports are a little smaller than the Felpro gaskets I used. New bolts and studs will have to be purchased as the new manifold does protrude farther out.

Regarding clearance, if you have old motor mount rubber, I recommend shimming the mounts at the K frame using fender washers or a steel plate to raise the engine slightly. This may be necessary with new mounts as well. Usually a 1/4" is sufficient, I do not recommend more than 3/4" as the stud on the motor mount will not have enough thread showing to be safe. If it isn't raised it could contact the steering box. This is the tightest clearance. Raising the engine this slight amount will not affect the drive train geometry.

With the thicker profile the passenger exhaust may to too close to the inner fenderwell. I used a 2" diameter steel pipe as a dolly the length of the log and a heavy hammer to make a concave surface. The collectors on both units curve in toward the engine slightly so the collector pipe does not even come close.

Another consideration is the fact that the collectors angle back rather than going straight down. On the passenger side it is important the pipe does not contact the floor board firewall intersection as 40 year old jute padding under the carpet will burn easily. You may find it necessary to dimple the metal at that point slightly and extra insulation is a good idea.

An excellent start to fabricating the exhausts would be to get a larger diameter Y pipe or dual system to section up and reweld it to clear obstructions. I used a Y pipe off of a 78 Diplomat for mine. I also routed the pipe over the starter and then down. Most auto parts stores have exhaust sections that can be welded together in a myriad of configurations as well. However you will need the flanged end of the collector pipe and a like diameter clamp.

With a little ingenuity you will find there are no insurmountable problems to making this modification."

 

[Dave_J]

I wish I had kept my letters from the late 1970's - early 1980's from Mopar's Direct Connection. I had wrote to Larry Sheppard's DC group and got an answer back.
I asked if running a 1965 273 Left side log with a 1970's 360 Truck's Right side log would hurt. Their answer was "While not optimized and not the best, it will not hurt the engine. If you can not get a set of headers to fit then you must do what is best with what you can get." Thorlies Tri-Y's were not being made and TTI was not hatched yet. "Stan's Headers" in Auburn WA wanted $850 for a set of headers back in 1979ish....

We had sealed the 273 manifold with silicone and poured in strong Hydrocloric acid and let it sit for 3 days till the silicone melted. This ate away a lot of the iron inside the manifold. We then filled it with BB's and mounted it on a paint shaker for a few hours to peen the insides.

Running the modified (a Little Less) restrictive 273 left log and the less restrictive 360 truck Right log did add a lot of power. But running the Iron 4Bbl 273 intake manifold we had an issue of the paint burning off the heat cross-over and I had to block it off. The right side was flowing so much better that it was pushing exhaust over thru the heat cross-over passage.

 

[AbodyTim]

I believe someone mentioned 60's 340 manifolds earlier. Probably well-known and written about previously is that '68-9 (Darts also?) 'cuda 340 manifolds as well as the complete exhaust system fits early A's (at least '65-6). My first '65 was the one my Dad put together for me in the late fall of '70. He used the complete system from the totaled '68 'cuda including the chrome tips (notched the rear valance for them) and it was a bolt-in. I have read of other folks doing it with no problem and others that had problems clearing the steering tube. Mine was a manual steering car with a floor shifter. Very costly thing to do with the price of 340 manifolds these days. I was going to replicate that car with the exception of using a 360 and magnum manifolds on the swiss-cheese Valiant I wound up giving to RustyRatRod.

 

[Dave_J]

I believe someone mentioned 60's 340 manifolds earlier. Probably well-known and written about previously is that '68-9 (Darts also?) 'cuda 340 manifolds as well as the complete exhaust system fits early A's (at least '65-6). My first '65 was the one my Dad put together for me in the late fall of '70. He used the complete system from the totaled '68 'cuda including the chrome tips (notched the rear valance for them) and it was a bolt-in. I have read of other folks doing it with no problem and others that had problems clearing the steering tube. Mine was a manual steering car with a floor shifter. Very costly thing to do with the price of 340 manifolds these days. I was going to replicate that car with the exception of using a 360 and magnum manifolds on the swiss-cheese Valiant I wound up giving to RustyRatRod.

The 1964, 65, and 66 273 manifolds are smaller inside than the A body 340's. And these early A body exit more downward to clear the firewall where the 340 ones exit more back and may interfere on the firewall.

I had around 3 sets of 340 A body manifolds but they went "POOF" over the years. One set went to Georgia on my 1965 Dart GT. I had to do some work to fit them but that was in 1984 so I do not remember what I had to do.

 

[AbodyTim]

Seems I do recall the drivers side was close to the firewall (only been 50 yrs. or so ) but it did clear.

 

[dartfreak75]

I used them on my 360 in my 75 dart. I just used grade 8 bolts and washers from the hardware store. I put some rtv on the wet holes (the 2nd time around because they leaked) I can't remember exactly the length but I just measured the manifold hole and then added another 3/4 of an inch.