Hello. I'm in a state of confusion. I'm looking for any sources on how I can obtain a correct flex plate for my 400 in my 74 Road Runner. The engine has a year "76" casting. The transmission is a Torqueflight.

The terrible vibration the car has, has let to a faulty 360 flex plate that someone drilled to make it work for the 400. The gentleman performing the transmission repair informed me that I need a wide ring gear, 2 weight, offset bolt pattern flex plate that will fit a 10 3/4 - 11 in torque converter.

This gentleman has requested such a flex plate twice and has received the wrong bolt pattern. The piece is for a 360. The supplier instructed him to simply re-drill and adapt to the 400, however, that is already the case.

I appreciate all your help.

look at b&m 10237


Chrysler '71 & later externally balanced 383, 400, 440 with cast crank and A-727 (These special Chrysler Flexplates must be used when changing converters on an externally balanced engine.)

I'd be looking for a new transmission repair man that is actually familiar with Mopars.

He knows what piece we need. His supplier is at fault. We've been trying to locate the correct part. I thought I'd ask around here to see what people have available. Thanks for sharing that information 70AARcuda.

I'm curious, why would the supplier recommend "redrilling" the flexplate? Are the bolt holes off or is the bolt circle incorrect?

Dude has a wire crossed!

You either need the external balanced flexplate that B&M makes (large pie cut out of one side of it) that uses a NEUTRAL balance torque convertor

OR

You need a torque convertor with the external balance weights attached.