shift kits for GM 400 Turbohydramatic

I believe your 412 has a GM TH400 model code FG. I don't think the trans is the problem. I think the torque converter in the issue. I've been looking around for the parts list to convert my 85' 400i trans to a switch-pitch converter. The idea being to switch to a lower stall speed above 20 mph. Kenne-Bell of CA offered a switch-pitch kit years ago.

 

I've ran B&M shift kits in the past on turbo400's. They are used all the time in drag racing. These will shift hard and FAST. WAY faster than a munual can. With these kits, you can taylor how hard and fast the trans will shift. It would be worth it to find some performance transmission shops in you area that can easily handle an install.


Darrell.

 

I rebuilt auto boxes for a few years; we always used TRANSGO in the 3 shops I worked in.

There is a cushion metal plate in each clutch drum that is designed to make the shift not so firm or harsh as some people would say. We used to remove them & replace them with a regular steel plate & then actually machine the clutch drum piston down so we could add another friction plate, that made for a long lasting trans with solid positive shifts, we also made some minor line pressure changes with the shift kit.

I would recommend just trying a shift kit first; the TRANSGO units will fix most of the common complaints on the turbo 400. Most re builders use TRANSGO; they are the originators of the shift kit, founder by Gil Younger back in 1959.

I believe the only difference in the Ferrari version of the 400 trans would be how many clutches were in the forward & high clutch drum.

I would not be surprised that it would be no different internally than for a GM truck that had a towing package that would require the additional clutches in the drums. I do believe that the cushion plates would still be in the clutch drums for the Ferrari version turbo 400 as the factory would probably want a transmission that was not harsh as say a Turbo 400 in a GM car or truck.

 

Sounds like the answer Nick.....

IIRC, with B&M, that was the deal, a high stall converter then messing about with the speed and severity of the upshifts....

All the drag guys used up the Hydroglides, which were two speed....only one upshift, per 1/4 mile!

 

Powerslides!!!

 

Powerglides...