magnum factory exhaust sizes question

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maca

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Hey guys
I have a 360 magnum with factory exhausts. I am installing it into a car with not much room around the exhaust so wanted to try and use the stock system. I have heard there are 2 different sizes. One apparently is bigger and will flow better. How do i find out what ones i have?
Cheers maca
 
Thanks
The Internal Measurement of my out lets is a Touch over 1 3/4 inches. I am in Australia and dont know what manny homes is. Is it a type of vehicle
 
maca said:
Thanks
The Internal Measurement of my out lets is a Touch over 1 3/4 inches. I am in Australia and dont know what manny homes is. Is it a type of vehicle
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Manny= manifold
Holmes=you

Two slangs don't make a slight. :D
 
Dang auto correct.

I just measured some from a 2000 5.9 at 1.9 inches.

If they fit in the engine bay, I plan to use them on my 318.

The factory 73 non-HP 318 manifolds measured 1.6, so that's a pretty significant increase.


IIRC 1992 was the largest, but not sure of the actual measurement.


Tell Manny Holmes we're sorry.
 
Mopar 360 magnum manifolds came in two or three sizes, the largest of all of them came with a 2 1/8" exhaust outlet. We're talking factory cast iron. Can you list the casting numbers on the manifolds that you have??

treblig
 
The sizes of outlets that I've seen (and I've seen a few) are 2 1/8", 1 7/8", 1 5/8". Mopar never made any manifold that had a larger outlet than 2 1/4" (340 manifolds). The 340 manifolds a just a hair over 2 1/4" (may 1/16" over). If yours are a little over 1 3/4" that's very close to 1 7/8". That would be the second best size outlet. The largest magnum manifold came with a 2 1/8" outlet (1990s).

Treblig
 
Thanks for the info.
I have seen on the turbo forums that guy's use these manifolds. They turn them around so they face forwards and then run a turbo setup. Can I still buy these larger manifolds brand new?
 
maca said:
Thanks for the info.
I have seen on the turbo forums that guy's use these manifolds. They turn them around so they face forwards and then run a turbo setup. Can I still buy these larger manifolds brand new?
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If you mean the 1 7/8" outlet manifolds, I do believe they sell them new. But why would you buy a new one when you can get a seasoned one from a salvage yard?? I prefer a seasoned manifold over a new one because a manifold that's been tested over thousands of miles is less likely to crack.

Treblig
 
Yes i see what your saying.
I am just trying to find the largest ones for flow as dealing with junk yards from Australia can be a little difficult. Buying new and shipping is easier but if they don't have what i need i will have to hunt around
 
maca said:
Yes i see what your saying.
I am just trying to find the largest ones for flow as dealing with junk yards from Australia can be a little difficult. Buying new and shipping is easier but if they don't have what i need i will have to hunt around
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Are you saying that you would rather have it shipped to you from the US than having to deal with salvage yards?? I have numerous large hole small block manifolds (340 and 360) and quite a few of the 1 7/8" 340 manifolds. I can post pics if you like but I don't know if you'd entertain paying shipping from the US??

treblig
 
The magnum engine was never released in Australia. Only the LA engines were.
So i cant buy magnum stuff here and if i ship second hand parts or parts from junk jards it can be difficult to get clearance.
Just trying to find the best flowing exhaust. I could buy block huggers if they flow as good. If i could find new ones they would be fine to ship. If i cant find new ones i may just have to take a chance.
 
Hey guys
Does anyone know it a set of block huggers for a LA 360 will be ok for a magnum? I think the LA verse magnum gaskets are different so not sure if the ports match up?
 
maca said:
Hey guys
Does anyone know it a set of block huggers for a LA 360 will be ok for a magnum? I think the LA verse magnum gaskets are different so not sure if the ports match up?
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I know that a '69 318 has smaller exhaust ports than a late 70s or early 80s motor. I don't think that magnum or non-magnum is a factor. I think Mopar changed the exhaust port design before the magnum engine went into production??

treblig
 
The ports are slightly different but I am running the same headers on the Mag as I had on a 318 without issue.
Could have something to do with the Remflex gaskets though, but I remember others on here with the same question and were told they are basically the same and anything made for the LA would also fit the Mag.
 
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