1969 Flexplate Ques

[Craig C.]

I have a 1969 427/390 with a THM 400 transmission which I am restoring to stock condition. The flexplate on the motor is 14" diameter w/ 168 teeth. There are no ID markings on the part except for 951 05 stamping. Is this enough info to determine whether this is the correct part?

My problem is that my transmission rebuilder suggested a Coan Engineering 12" #20102 torque converter which, according to Coan's website, probably should fit this application. However, the flexplate's bolt holes do not match up with the torque converter's holes. The holes on the flexplate are about 5 and 3/4" on the radius while the torque converter's holes are 5 and 1/2". This is very frustrating and I am trying to figure-out which is incorrect - the flex plate, the converter or both?

Thanks in advance for any help offered.

Craig #32671

[Joe L.]

Re: 1969 Flexplate Ques

Craig-----

The OD of the flexplate is correct for your application. I can't tell anything from the numbers.

Most flexplates for your application were originally of GM #3937736. This flexplate has TWO mounting hole patterns which are "staggered". The inner pattern is 10-3/4" in diameter and the outer is 11-1/2" in diameter. If your flexplate is configured like this, I feel very confident that it's the right one. If it's not configured like this it may or may not be the correct one.