Magnum flex plate 904 vs 727: identification?

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MRGTX

MRGTX

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So my 904 is ready to be picked up and installed on my Magnum crate engine.

The engine came with the flex plate but It just occurred to me that it might not be compatible with my 904 and that this might be a problem since I believe I heard that the 904/magnum flex plate is no longer available :banghead:

How can I tell? The plate is about 12" in diameter...
 
It seems like the magnum flex plate topic is voodoo...

I'm just going to assume that I have a 727 diameter flex plate since they're presumably more common. :(

I just called Performance Automatic just to see if they had the right flex plate and the guy knew nothing about Mopar flex plates...they didn't even sell them (despite offering quite a few choices for Mopar transmissions).

If I'm reading the "Magnum Swap" page correctly, I will have to buy a standard Ram/Dakota Magnum Flexplate, then get a torque converter that is weighted specifically for a Magnum...and there's basically only one shop in the whole world that will make one of these?

:wack:

How will I know if the diameter of the stock flex plate will even work with the 904?

Can anyone generous soul offer any other ideas?

Thanks in advance!!
-Mike
 
sledger46 said:
If you buy the flexplate for a Ram/Dakota in the right years, the flexplate will already have the weights on it and you can use a neutral balance converter. I think mine came from a 99 Durango. Here is a like to what I bought:

http://www.ebay.com/itm/30072816126...iewitem=&sspagename=ADME:L:OU:US:3160&vxp=mtr

You can see the magnum specific weights on the flexplate.
Click to expand...

Thanks, Sledger46!! This is a huge help. I was under the impression that the Dakota/Durango flex plates were all neutral... I just got a quote for a custom Magnu-balanced torque converter that almost made me sh-- my pants (it would be damn near $1000 shipped!!)...

I just couldn't swing that...So this might be a huge life saver. :glasses7:
 
MRGTX said:
Thanks, Sledger46!! This is a huge help. I was under the impression that the Dakota/Durango flex plates were all neutral... I just got a quote for a custom Magnu-balanced torque converter that almost made me sh-- my pants (it would be damn near $1000 shipped!!)...

I just couldn't swing that...So this might be a huge life saver. :glasses7:
Click to expand...

if it was me, i would hit up the local parts yard. i bet you could get one with the bolts for less than 20 bucks.
 
Look guys, all you have to do is elongate one hole on the mag flex plate, and your good to go. You pick one, done. I'd take a pictue of mine, but I'm tired of rolling on the ground for the moment.
 
PoisonDart74 said:
Look guys, all you have to do is elongate one hole on the mag flex plate, and your good to go. You pick one, done. I'd take a pictue of mine, but I'm tired of rolling on the ground for the moment.
Click to expand...


Yeah...that sounds like what LXGuy posted on his excellent Magnum Swap page.

What was entirely missed by me was that the stock Magnum flex plate was weighted... I thought the elusive (out of production) B&M one was special and desirable because it was weighted...therefore the only alternative was to get a stock plate (incorrectly assumed to have no weights) and a specially made/weighted torque converter! That would have been pricey.

BTW, it goes without saying that the stock Magnum flex plate is the right diameter for the 904...right??
 
MRGTX said:
BTW, it goes without saying that the stock Magnum flex plate is the right diameter for the 904...right??
Click to expand...

Yes, it was what LXguy said and all the others including myself that have done this swap. Yes, it is the right diameter and everything for the 904, go make it happen. I smell burnt hair from all the over-thinking. :mrgreen:
 
MRGTX said:
It seems like the magnum flex plate topic is voodoo...

I'm just going to assume that I have a 727 diameter flex plate since they're presumably more common. :(

I just called Performance Automatic just to see if they had the right flex plate and the guy knew nothing about Mopar flex plates...they didn't even sell them (despite offering quite a few choices for Mopar transmissions).

If I'm reading the "Magnum Swap" page correctly, I will have to buy a standard Ram/Dakota Magnum Flexplate, then get a torque converter that is weighted specifically for a Magnum...and there's basically only one shop in the whole world that will make one of these?

:wack:

How will I know if the diameter of the stock flex plate will even work with the 904?

Can anyone generous soul offer any other ideas?

Thanks in advance!!
-Mike
Click to expand...
It's not Voodoo. The flexplates are the same for an internally balanced Magnum as they are for an LA motor.

I've got an LA SFI rated flex plate on my 390 that's in front of the 904 in my Dart.
 
MRGTX said:
Thanks, Sledger46!! This is a huge help. I was under the impression that the Dakota/Durango flex plates were all neutral... I just got a quote for a custom Magnu-balanced torque converter that almost made me sh-- my pants (it would be damn near $1000 shipped!!)...

I just couldn't swing that...So this might be a huge life saver. :glasses7:
Click to expand...

For mine, we just bored out all four holes equally.(my friend was afraid filing just one might upset the balance)

What i wonder though, wouldnt it be easier/cheaper to take a neutral balance LA-904 flex plate and have it balanced/weighted for a magnum motor?
 
magnumdust said:
For mine, we just bored out all four holes equally.(my friend was afraid filing just one might upset the balance)

What i wonder though, wouldnt it be easier/cheaper to take a neutral balance LA-904 flex plate and have it balanced/weighted for a magnum motor?
Click to expand...

Only if it's a 360 Magnum. The 318's are internally balanced.
 
rnaz said:
Don't slot holes in a flex plate. That's being a hack.
Click to expand...

It's not that big of a deal. Plenty of things more important on these vehicle's than if you elongated a bolt hole here or not. :roll:

If you still feel we just have to buy a new flex plate or we're going to witness some huge tragedy because of it, then you go right ahead and buy it for all of us who have, or will do the swap.
 
Same ss Poison74. Offset the one hole,notched it,to clear the torque converter billet stock.Those stock flexplates,rigid as hell.
 
PoisonDart74 said:
It's not that big of a deal. Plenty of things more important on these vehicle's than if you elongated a bolt hole here or not. :roll:

If you still feel we just have to buy a new flex plate or we're going to witness some huge tragedy because of it, then you go right ahead and buy it for all of us who have, or will do the swap.
Click to expand...

The right parts for the swap are available. Why not just use them? I provided a link to the inexpensive part number that's SFI rated.

A standard LA flexplate will also fit a magnum crank without opening holes up.
 
If you don't have the coin? Make what,you have ,work Not everyone,bucks up.....
 
Any LA flexplate will work. Even a junkyard one that's not cracked. They can be had for $5 or so. Opening up a hole in a part that requires the engine and trans to be separated to change out is just a good way to be really pissed off when that plate cracks and you have to waste a whole day changing it.

If you're spending the time and money on a crate engine, why not just do it right?
 
I didn't do crate.Maybe I need to explain. Started ,with a Y2k ,Magnum used.I prefer ,running stock balance parts,anywhere. Modiified,what I had ,to work. Very happy ,with the results.
 
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