Cracked 360 Magnum Flexplate

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snailpower

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Coming hot off of some of my best times at the strip I heard a ticking noise at idle a couple days later. I checked the converter bolts because it sounded to be coming from that area and found some good cracks and a nice engine vibration to match.

So, I need a new flex plate and don't want to use another stock one because I don't want to do this again. I will probably also be upgrading my converter at the same time because this 2200 stall isn't cutting it. Currently using the neutral balance 318 converter with the stock mag flex plate and professional products balancer.

What are my options for aftermarket flex plate / converter? It seems like an aftermarket flex plate for the magnum 360 / 904 is hard or impossible to find. Does anyone know any different? I am thinking of Ultimate / PTC for the converter.

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good catch, ALL 318's were neutral, even the mags. All 360's were not. Does your PP balancer include the 360 magnum weight? If it does and your all balanced, Get a neutral balance solid plate like a B&M
shopping
 
good catch, ALL 318's were neutral, even the mags. All 360's were not. Does your PP balancer include the 360 magnum weight? If it does and your all balanced, Get a neutral balance solid plate like a B&M
shopping

My PP balancer is balanced for the 360 yeah (has an offset weight on it), current plate is weighted (stock mag plate) and converter is neutral from the 318 that came out. I would think a neutral plate would throw it off no?
 
My PP balancer is balanced for the 360 yeah (has an offset weight on it), current plate is weighted (stock mag plate) and converter is neutral from the 318 that came out. I would think a neutral plate would throw it off no?
yes it will
I believe B&m quit making a Magnum 360 904 flexplate. You could get a neutral 904 plate and buy your converter weighted for 360 magnum.
 
yes it will
I believe B&m quit making a Magnum 360 904 flexplate. You could get a neutral 904 plate and buy your converter weighted for 360 magnum.

Looking like thats my only option. Hoping that I don't get raped on cost having it balanced for the magnum.
 
Yes you are correct, B&M does not make the 360 magnum to 904 flex plate any longer, stupid I think. I have used the 360 magnum to 727 flex plate and trimmed down the nose of the starter to make it fit. But as said above Turbo Action makes one and would probably be the cheapest way out. Also if your changing out the convertor you could just have it made to the magnum balance spec and use the neutral flex plate. Just make sure you know which year 360 magnum you have they are not all the same. It would be the same thing in the end.
 
I dont know if the weight on the PP balancer is used in addition to the flex plate weights, seems alot of weighs in different places to balance a motor. I know the convertible PP balancer had 2 weights, a 360 LA and a 360 mag. would any of those be enough with a neutral flexplate? That one thing I hate about a 360, the balance issue.
 
Yea I hear you pishta. The 360 balance it a PITA. I just had a idea. Why can't he take the weight off the flex plate he has and weld them on a new neutral flex plate? We used to do that to torque convertors back in the day. Hell I remember Ma Mopar sold the weights as a kit. Don't think it would have to be SFI approved as he is running a stock flex plate now.
 
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Yea I hear you pishta. The 360 balance it a PITA. I just had a idea. Why can't he take the weight off the flex plate he has and weld them on a new neutral flex plate? We used to do that to torque convertors back in the day. Hell I remember Ma Mopar sold the weights as a kit. Don't think it would have to be SFI approved as he is running a stock flex plate now.


That would be awesome, but I would really hate to get the motor back in and have it vibrate because the weight was off a fraction of an inch.

Looking at rock auto a stock replacement plate is only $40, wish it was stronger! haha. Its possible mine was just worn out, its the one that came off of the 110k motor before I built it so who knows.

Yes you are correct, B&M does not make the 360 magnum to 904 flex plate any longer, stupid I think. I have used the 360 magnum to 727 flex plate and trimmed down the nose of the starter to make it fit. But as said above Turbo Action makes one and would probably be the cheapest way out. Also if your changing out the convertor you could just have it made to the magnum balance spec and use the neutral flex plate. Just make sure you know which year 360 magnum you have they are not all the same. It would be the same thing in the end.

yeah I will probably give them a call in the next couple days and see what the say. Sounds promising. I am down to spend the money on the converter, but if its a huge jump in price for magnum balance thats kind of a bummer.
 
Much mis-information is still out there on 360 Magnum engine balancing.
All 360 Magnums should have the same balance weight. The difference is where the factory placed the actual weight. Some years had weight on the flex plate, some years on the convertor. Some years had a two piece pulley and balancer while later years switched to a one piece integrated pulley and balancer assembly.
Bottom line is if you have a factory Magnum rotating assembly, use the factory balancer or correct weight on the Professional Products balancer, and you get a properly weighted flex plate, you can use a neutral balance convertor. That is exactly how the OP had his set up.
If you cannot find the correct weight flex plate currently being produced, try finding a used B&M number 10242. That should be for Magnum engines running neutral balance convertors.
 
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