Reinstalled motor and trany this weekend in my 63 390 and jetaway after overhauling both. Problem: the torque convertor is about 3/16" away from making contact with the flex plate. When I try to tighten up the flex plate nuts the flex plate flexes or bends.   questions: should the torque convertor have some movement to make contact with the flex plate or is it solid no movement? And does the nose of the torque convertor go into the back of the crank shaft?  I'm thinking the back of my crank is rusty since its not the crank that camo out of the car, stopping the convertor from moving forward.

Thanks for the feed back.


Views: 91

Reply to This

Replies to This Discussion

Are they the engine and trany that were in the car before or was something changed ?

Stay safe 

Are you implying you changed the engines original crankshaft ?

The 1964 Turbo Hydramatic flexplate has a 3" opening. The raised back end of the 1963 390 Hydramatic crankshaft and 1964 429 Hydramatic crankshaft is 3 3/16". The flex plate is not going to fit the Hydramatic crank unless it is enlarged to exactly 3 3/16" and it has to be exactly centered!  It sounds like you are trying to mate a 1964 429 Turbo Hydramatic to a 1963 390 which came with the Hydramatic crank. For more details on this and other issues you will run into check out this help page: Engine and Transmission Facts - differences from 62 to 63 to 64 to 65

Be sure to scan down to the Swapping Transmissions - Things to Consider section.

All 390’s in 63 had  the hydromatic trans 

In 64 the 429 —had two trans  mounted to the engine depending on the model Cadillac in 64 

Two  different crankshafts  size ends —-came in the 429  engine in 64 

One size crank —was for the hydro trans 

A second size crankshaft  in the 429 —came in the engines that got the turbo (400) hydro trans which has a spacer in 64 year only 

The correct engine  must be used  with the correct trans depending on the engines crankshaft   End size and —they are not interchangeable due to the size of the crankshaft end that couples to the trans being different 

This will cause a major complication  in matching the correct engine to the correct trans if not done correctly 

As noted in the above post by Jason then a good number of other issues will have to be addressed 

Dropping a 429 with a hydro trans —that came that way in a given 64 model - would work in any Cadillac in 63 or 64 that originally came with the hydro trans making that swap correct and very much less complicated to get done correctly 

Having  two different crankshaft sizes in the same engine in a given year is completely unique to the 64 429 engine very much complicating a trans swap if not understood clearly 

Stay safe 

Thank you all for the comments. I had to change the engine due to a cracked block. I got an complete 63 390 short block, (thank you Russ). completely rebuilt it, but I failed to clean the rust out of the back of the crank where the nose of the converter slides in. I gave the flywheel a couple love taps with a brass hammer and it moved forward just enough. The convertor must move freely in the back of the crank for ballooning.   


Glad it was an easy fix. It was ironic the # you used 3/16" which is the exact different in diameter of the 1963 drive plate and 1964 flexplate.

Glad it turned out to be a simple issue that you worked thru 

Always the best case scenario 

Enjoy having your car back in action 

Stay Safe 



  • Add Photos
  • View All


Whoa there, you want how much??

Started by Robert Gonzalez in 1963/64 Cadillac Specific Discussion 15 hours ago. 0 Replies

Ok, I’ve been on here for almost a decade. I KNOW we covet our cars and have always tried selling them at premium prices. But the bottom line, our cars rarely fetched prices over a covair. The…Continue

1964 Cadillac parts for sale... northern cali

Started by Jason in For Sale. Last reply by Jeremy yesterday. 1 Reply

Bill Hirsch cast iron gray exhaust and manifold paint (1 can) $20Bill hirsch Cadillac dark blue engine enamel high temp high gloss (2 cans) $40Convertible top latchValve coversHeadlight bezelRadioGas…Continue

Tags: Parts

63 4 door Cadillac

Started by Walt Timmerman in For Sale. Last reply by Jeremy yesterday. 7 Replies

Need to start parting this car out. Might be moving soon and if its not parted out, it'll be scrapped.Also have Motor and transmission from my 63 coupe deville for sale. will part out also.Was told…Continue

Free- 64 lower bumper bucket - Passenger side

Started by Michael Buonaccorso in For Sale. Last reply by Jeremy yesterday. 1 Reply

This is in rough shape. Not only is there rust in the usual places but it is also bent. I replaced this piece on my car after an accident, but since this is a hard to come by piece, I figured someone…Continue

Blog Posts

Rumble Sound at 55-60 mph

Posted by Ray Schick on September 20, 2021 at 10:45pm 6 Comments

64 Coupe DeVille , while driving at 55-60 mph I have a oscillating rumble sound . Steering wheel does not shake or vibrate . Transmission mount looks good .Tires were replaced 2 years ago balanced and rebalanced recently. Axel bearings were just replaced, rear differential assembly was just replaced with a Posi track ,pinion bearings good. Fresh gear lube. Driveshaft checked and balanced the other day ,new center bearing installed and new bearing carrier assembly too. Trying to figure this…


1963 series 62 convertible transmission issue

Posted by Matthew VanDeWater on June 22, 2021 at 3:03pm 1 Comment

Hello I've been restoring a 63 for way to many years. Down to almost done, but have issue with trans linkage, when column in park shift rod 2 inches short. everything original. been trying to find picture of manual rod hooked up from under car to see position of linkage. was wondering if anybody has access for pictures. I wanted to see if my manual linkage is bent  wrong out of the trans if somebody dropped the trans or something. Doesn't make sense why it doesn't work. Thanks for any input…


New vehicle in the club

Posted by Patrick Westphal on June 17, 2021 at 4:00pm 1 Comment

I was successful in getting a vehicle from the New York contact I talked about at the last club meeting. I am still trying to figure out how to post a picture of the vehicle that is tied with this comment so if you see a random picture of a black convertible in a yard, that's me haha.  …


Torque converter grab when idling in Drive

Posted by Cliff Johnston on June 14, 2021 at 8:47pm 2 Comments

Hi Everyone, been quite a while since i have been on here.

I have had an issue with the idle on my 64 Coupe Deville ever since i have had it.

With the Idle set high enough that it is smooth, but still a nice idle, the RPM seems only slightly too high for the stall of the Torque Converter. And therefore it tends to sit there and grab and lunge a bit. So until now, i have been putting the car in Neutral at the lights to stop this happening.

I've had the car dyno tuned and…



  • Add Videos
  • View All

© 2021   Created by Jason Edge.   Powered by

Badges  |  Report an Issue  |  Terms of Service