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Still confused on my 727 Torque Converter problem. With pictures.

SteveSS

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I got raked over the coals for not asking for help from you guys before I bought it. It's supposed to be a lightly used, after it's rebuilt 727 big block trans. I had to drive from Colorado Springs to Albuquerque to get it.

The problem showed up during installation. My flex plate is slightly different than the TC. You can see from my photos, the flex plate has one offset hole. (by the white scrap of paper) The TC's bolt pattern is symmetrical. We found some stamped numbers on the TC but they didn't match anything on a long search.

I bought a cheap TC from Auto Zone for $110, but it wasn't even close. I could hog out the one hole from the TC, but the internet says it would cause vibration.

What to do? What the heck is this TC from? Do they make a flex plate for this?

727 1.jpg
727 2.jpg
727 3.jpg
 
Even spaced holes on the T C are normal for 91 up magnum motors.
(Could be 92)
If you want to use your new converter, get a later flex plate.
Caution, later flex plates come zero or 360 counter weight only.
You didn't specify what motor you have. Big block, but I hope not cast crank 400/440.
 
I talked to a transmission guy and he said what I have is a 90 degree TC. I need the offset one. Sorry I used the term flex plate when I meant pressure plate.

So do I need to put on an externally balanced TC? I have a 1971 Charger 500 with a 383.

Fixed it in the original post.
 
Last edited:
You were right the first time.
Flex plate.
If you have a 90° later style converter, you need a later flex plate.
Early, like pictured, are offset.
 
Don't see any counter weight on the TC, so it's for an internally balanced engine. Make sure your motor is internally balanced. I think the 71 time frame was when things started to go from internal to external balance on the motors.
 
Not seeing one on ebay. So will a 90 degree flex plate and TC work with my older 727 and '71 383. Are the 90 degree ones the big gold ones with a half moon chunk missing?
 
90° is the newer style.
The gold one, (moroso) is just a brand identifier.
They may make one that is 90°, and another that is staggered, that look tge same.
The half moon chunk is a counter weighted flex plate. Not what you want for a 383.
For reference, a picture of the new magnum style flex plate.
It will interchange to your crank.

20251029_191626.jpg
 
Oblong the hole and run it. It wont hurt anything since your engine doesn't require external balaamce.
Doug
 
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