troys2222

hello, my question is what will i need to do this conversion?

will i need a electronic kickdown?

and what converter? will they swap over th 200 th350? converter?



Thanks Troy.

joe_padavano

What is the car? The TH400 requires the crossmember to be moved rearward. If you have a car that had a TH400 as an option, the holes are already in the frame in the correct location. If not, you'll need to drill new holes. If you have a convertible with a boxed frame, you may need to weld an extension to the tabs currently on the frame.

The Junkaway, er, JETaway, also uses an electric kickdown, so just plug it in. A non-lockup TH350 converter will work in a TH400, but why not just get the right one for your application?

The TH400 uses a larger yoke than the Jetaway and TH350, so you'll need one of those. The driveshaft for a TH400 is shorter due to the longer trans, but if you're lucky you can sometimes use your existing driveshaft. If you want to check, push the yoke all the way into the trans and pull it out about an inch. Measure the yoke-to-yoke distance. If your current shaft is within 1/4", you're good to go. Otherwise, get it shortened.

troys2222

Thanks joe the auto is a 69 cutlass convertible. the th 400 is a short tail transmission.

dan1s

Hi,

I just got done doing this exact same swap in my 68 Cutlass. I had to get a different driveshaft. I picked up a used one from a 69 Pontiac GS. Along with the drive shaft I needed to get a special U joint to go from the driveshaft to the rear. They were two different sizes. I also had to change the trany mount (the holes that go into the trany were a little off) . You will need to move the cross member back around 6.5 inches. I had holes in my frame for this. Another thing is the shifter column, you might have problems with putting the car into first gear. I lucked out and was able to get my car into first gear.

What year is the Trany? Mine is a 1977 and the kickdown wire went to the vertical terminal on the trany. If you have two terminal's the horizontal one was used for a spark control (emission's crap) you don't have to use this.

If you need any measurements on the drive shaft let me know. A driveshaft from any "A" body car from 68-72 that had a TH400 in it should work.

Good luck

Dan

joe_padavano

Just to clarify, the 65-67 TH400s with two terminals are the switch-pitch transmissions. The second terminal operates the solenoid for converter stator angle. Rare and somewhat desireable. As Dan correctly points out, the 71-up TH400s with two terminals use the second terminal for the transmission controlled spark retard feature.