What have I got here? Magnum 5.9 Flex plate identification

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MRGTX

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Heyah, guys.

Sorry for the crappy pic...this is the "disk with the bite taken out" style flex plate, approximately 12" in diameter....

Basically, I'm hoping for some more guidence as I prepare to install my Magnum 5.9 crate engine that I bought used from another forum member along with my 904.

Question 1:
A far as I know, this is the original part. The engine was previously run with this flex plate...but is this flex plate too big for use with a 904? I can't find the correct measurements anywhere!

Question 2:
If it is the wrong plate for use with the 904, I understand that a stock Magnum flex plate can be used...but that there are different types (weighted versus non weighted) based on the year of the Magnum. Based on what this engine came with, can you tell which I would need?
Thanks a million for any help..

It seems that the stock Magnum flex plates are available from Rockauto, etc...

Thanks yet again!
-Mike
 

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That's not factory, it appears to be B&M, and there should be a part number which you can Google.

Not knowing the part no. or where it came from, it could be (example) for a 360 LA with a neutral converter, so, completely wrong for your current app.
 
That's not factory, this is factory, neutral balance is the name of the game here:

318%20Magnum%20flexplate.jpg
 
B&M 360 magnum 10242 727
B&M 360 magnum 10241 904

i do not know if you can make it work
 
So i ordered up a stock weighted Magnum flex plate from Rock Auto since according to MagnumSwap.com, folks had used these successfully with the 904...or thats how I interpreted what I read.

Well, it showed up today and it's the exact diameter of the B&M unit that is used with the 727. :banghead:

Umm... So is that pn 10241 B&M flex plate the ONLY way to mate a 904 up with a Magnum?!!

Somebody else must have done done this before...right?
 
No, all you have to do is elongate one bolt hole in the stock mag plate, put the mag plate over the 904 TC and you'll see what I mean.
 
The total diameter means nothing as long as it fits in the bellhousing without hitting anything while rotating and has the correct diameter bolt pattern for your converter (10 or 11"). The original flexplate you got with it might work with a 904. By the looks of it it has at least 2 sets of holes for different diameter torque converters. My guess is the inner set are the right size for a 904 converter.
 
Wow...ok... so in honesty, I have yet to try to fit the bell housing up to see if it fit. I just assumed that it had to be too big for the 904 since there are different parts for the 727 and the 904.

So if the flex plate does fit inside the bell housing, the trick will be finding a ring gear that will extends beyond the edge of the flex plate, right? Can these be swapped?

Thanks for the info, guys.
 
The A904 stock torque neutral weight converter fit's like a glove, yeah, the kind you buy out of a catalog.

No extending, no welding on a balance weight, no dicking with it, minus a little zip of a drill bit. Better yet a dremel with a grinder bit to extend one hole in the Magnum flex plate.

Don't create a problem that doesn't exist, or over think it. That's it. That's it. That's it! :violent1:

Here is a link, explaining the deal with pictures.

http://www.forabodiesonly.com/mopar/showthread.php?t=43757

Enjoy! :D
 
Wow...ok... so in honesty, I have yet to try to fit the bell housing up to see if it fit. I just assumed that it had to be too big for the 904 since there are different parts for the 727 and the 904.

So if the flex plate does fit inside the bell housing, the trick will be finding a ring gear that will extends beyond the edge of the flex plate, right? Can these be swapped?

Thanks for the info, guys.

Your over thinking it. The main difference between 727's and 904's is 727's came with either 11 or 12" converters and 904's came with 10 or 11" converters so the main difference between them is the bolt circle. Ring gears are not easily changed on a torque converter because their welded on but you don't need to worry about it anyway because I doubt it'll be an issue. I believe they only come in one size for automatics. If you think about it the starter bolts up only one way and is not adjustable so it's in a fixed relationship with the ring gear therefore the ring gear can only be one diameter.
 
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