Factory Flexplate Durability (440HP)

[Goldmember72]

I have a 72 Charger 440 HP. I know most will say to replace with aftermarket and I don't have a problem with doing that. I would like to know how many have had a factory flexplate failure or found one damaged when being removed? I would think they should be able to handle 400 HP due to the ratings of the 440 prior to 72.

 

[69 GTX]

If you have it apart, replace it. For the cost of the flex plate do you want to risk pulling the engine or tranny again due to a failure?

 

[Goldmember72]

If you have it apart, replace it. For the cost of the flex plate do you want to risk pulling the engine or tranny again due to a failure?

I do plan on replacing it but still would like to have an idea how many have had a problem using them again. I agree for the cost I personally don't want to be going back into it.

 

[Darter6]

Like anything parts fail. It's just we don't know when. I have used them over and over many times without a problem. Best to inspect for cracks and bolt holes. BUT,,If in doubt,,replace.

 

[RT K_line]

I'm running one now and have only had one break years ago when my bellhousing bolts were loose and I didn't catch it. I do have a solid one in the garage I will change when I find a lower stall converter. I'm running a 4200 stall now running mid 12s without any problems, Knock on wood, lol.

 

[Yatzee]

I have a 72 Charger 440 HP. I know most will say to replace with aftermarket and I don't have a problem with doing that. I would like to know how many have had a factory flexplate failure or found one damaged when being removed? I would think they should be able to handle 400 HP due to the ratings of the 440 prior to 72.

Your question is somewhat "moot" because there are far more Mopar owners than listed on this board. As far as the flex plate goes, it all depends on how you drive the car - Sunday driver or "pedal to the metal". One thing is for sure, when they go it's usually serious results.
Some people are a bit paranoic with an item buried so deep in the power train and change to a better quality plate, and some never think of it and drive without incident. Obviously the issue has crossed your mind and you seek an answer to a question that really can't be answered because people usually upgrade this item especially with a costly motor and/or tranny rebuid is done.They don't really wait for the time of failure if at all.

 

[PRND21]

If you’re planning on racing it, don’t you have to have one with an SFI number?

 

[69 GTX]

Yes but I'm not sure of the ET where it is required.

 

[66Satellite47]

I've used the after market B & M, and Turbo Action flex plates for many thousand runs. Each worked well. Get an SFI rated version and don't worry.

 

[SublimeSixpack]

To answer your question; no I've not had a problem with the stock flex plates.

 

[1967coronet440]

I don’t see a factory plate being an issue with 400hp

 

[Goldmember72]

Thanks to all that have replied. I understand there is a much larger group of Mopar owners to sample data from but I am glad to see my opinion on this seems to match up with some others.

 

[moper]

I've owned one SFI flexplate in my life. That includes running some engines close to 550hp, and a nitroused 383 in a C body (lots of weight). Never broke one. But I've replaced others that cracked on the owners with stock engines. I wouldn't hesitate reusing a factory one unless the expectation was faster than the NHRA requirements (I think that's 11.49 or faster?).

 

[66Satellite47]

Depends on which factory flex plate you would use. Early parts, '60's & early '70's seem fine. Later factory I would question. A good SFI rated version will hold up to a lot of power.