61 buick lesabre transmission

[Nickbailey016@gmail.com]

I was wondering if it was possible to swap a 2 turbine dyna flow transmission for a 400 automatic and if the was a conversion plate that would be needed to do the swap.

[61polara]

I understand you will have to change the crank shaft in the engine.  

[NTX5467]

1965 Wildcat used the THM400 behind a Buick 401 engine.  One of our chapter members had his '62 LeSabre converted to the THM400, using a trans and related items from that particular '65 Wildcat.  He was surprised at the difference it made.  His then-teenaged son then wanted to drive the car, but was not allowed to do so.  Just a plain swap, as I recall.  Not sure if the same would work on a '61 vs. '62, though.

 

Be advised that there are TWO bolt patterns on a THM400 and most other GM automatics.  The common "Chevy" pattern and the "Buick-Olds-Pontiac-Cadillac" pattern.  Which is why starting with a Buick-case THM400 is important.  PLUS getting the related "switch-pitch" switches for the carb linkage.

 

Enjoy!

NTX5467

[Bloo]

I believe the Turbo 400 for the Nailhead Buick has a third bolt pattern, neither Chevy nor BOP. The bellhousing is also shorter and used a spacer plate, making it very adaptable. I have heard the Nailhead transmission was used with adapters in other makes when used with non-GM engines, such as the AMC/Jeep 287/327, and maybe a European application or two.

 

EDIT: Make that four patterns. There is a fourth one native to the last generation AMC v8s (not the 287/327 that used the Nailhead transmission).

Edited May 14, 2020 by Bloo (see edit history)

[seeholmes]

ST400 from 64-66 Buick is what you want. You will need a crank bushing, flexplate, new starter, different driveshaft, move the trans cross member. Also need to figure out how to switch the electrical switchpitch as compared to the mechanical dynaflow. Then there is the shift linkage also as the dynaflow pattern is P-N-D-L-R and the ST400 is P-R-N-D-L1-L2. Also I assume the spedo gear would need to change to get accurate speed.

 

Ive considered this swap a few different times but keep ending up with keeping the dynaflow. Its a big part of the cars "personality". If your set on switching you may want to consifder a 4L60E overdrive transmission. If your going through all the hastle of switching thats what I would do.