Pre-magnum flexplate on a 46RH?

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FatNancy

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Please pardon my ignorance. I plan on using a BPE 408 (360 magnum) with a '95 46RH transmission (A518 with lockup). Techs at BPE recommended using a neutrally balanced torque converter with a weighted, pre-magnum flexplate. My question is, would the LA flexplate work with the 46RH?

Maybe the better question is, would the A518 flexplate and torque converter work on the BPE 408? I would have to doublecheck, but i think the torque converter is weighted and the flexplate is neutral
 
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FatNancy said:
Please pardon my ignorance. I plan on using a BPE 408 (360 magnum) with a '95 46RH transmission (A518 with lockup). Techs at BPE recommended using a neutrally balanced torque converter with a weighted, pre-magnum flexplate. My question is, would the LA flexplate work with the 46RH?
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Not being a smartass at all, but Blueprint sells that combination everyday. Call them and see what they use. @Johnny Mac is their rep and a member here. I tagged him so maybe he'll chime in with some help. Welcome aboard!

I may have spoken too soon. I looked on their site and all I see available is the 727 on the small block package. Johnny should still be able to help though.
 
Factory LA flexplates are non-weighted. Assuming (!) they want you to use the LA 360 balancing (the 5.9 Magnum is different), you would need an aftermarket flexplate like the B&M 10239. If you need the Magnum balance, use the 5.9 Magnum flexplate- one hole needs to be elongated, otherwise it'll bolt up. Wait for Johnny Mac to tell you which one you need, otherwise call them.

"Maybe the better question is, would the A518 flexplate and torque converter work on the BPE 408?"
That depends on whether the A518 flexplate was on a 5.2 or 5.9.
 
Alright fellas! Happy to help. Our 408 is balanced on the rear as an LA 360. So we recommend an LA 360 balanced flexplate.

You are correct that the factory flexplates were neutral, but the commonplace aftermarket is a NEUTRAL converter, and then you use the proper balance flexplate.

Some transmission companies do still balance the converters but most don't

I guess My answer would be I don't care if the flexplate, or the converter, get balanced to LA 360, but one does, and one needs to be neutral.

Next thing would be to make sure that torque converter is stalled properly....a factory one will kill that engine.

If its a Magnum balanced converter that you happen to have already.... knock the weight off and get an LA 360 balanced flexplate

The later model chrysler transmissions kept the same 727 or 904 converter patterns. I just don't remember if the 518 was 727 or 904 based without Google.

Let me know if questions remain after all that!!
 
Professor Fate said:
Assuming (!) they want you to use the LA 360 balancing (the 5.9 Magnum is different), you would need an aftermarket flexplate like the B&M 10239
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The tech said pre-magnum balancing, so I'm pretty sure your first assumption is correct. But would a flexplate like the B&M 10239 work with a 46RH?

Professor Fate said:
That depends on whether the A518 flexplate was on a 5.2 or 5.9.
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It's from a 5.9
 
FatNancy said:
The tech said pre-magnum balancing, so I'm pretty sure your first assumption is correct. But would a flexplate like the B&M 10239 work with a 46RH?
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I think I misspoke- 518/46RH are 727 based, so you need a B&M 10236. The 10239 is for 904 and it's derivative (A500/42RH) trannys. I apologize- I've had 904s on my mind lately.
Anyway, you've got the word from Johnny M. himself now- good luck!
 
Professor Fate said:
I think I misspoke- 518/46RH are 727 based, so you need a B&M 10236. The 10239 is for 904 and it's derivative (A500/42RH) trannys. I apologize- I've had 904s on my mind lately.
Anyway, you've got the word from Johnny M. himself now- good luck!
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Gotcha, thanks! I just realized that the 727 and a518(46RH) use the same flex plate and torque converter, so I'm good to go.

I really appreciate the help.
 
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FatNancy said:
Gotcha, thanks! I just realized that the 727 and a518(46RH) use the same flex plate and torque converter, so I'm good to go.

I really appreciate the help.
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The standard 727 does not use a lockup torque convertor, the A518/46RH does- they're different! Different splines, etc. Factory flexplates are the same, though. But that's why you need the B&M flexplate in order to run a neutral balance convertor- they put the LA360 balance into the flexplate instead of on the convertor.
 
You are correct. I just meant that the bolt pattern is the same between the 727 and the 46RH. I should have been more specific.
 
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