5.9MAG/trans into 65 Valiant
Well, here's the some pictures of the Torsion Bar Surgery for the Mopar overdrives versus a 200R4. The first is the minor mod for the 200R4. The second is what gets cut out for the Mopar units, which take A LOT more power to turn. Both will have to have new rear transmission mounts made. You would have to figure a way to reinforce the Torsion Bar Crossmember, which many people have done successfully. A concave plate can be welded into the small hole cut in the Torsion Bar Crossmember to strengthen it too.
Your 4 wheel drive trans won't work at all anyway. It's a different animal. You will have to use a computer controlled Mopar overdrive out of a similar year car with your computer though, as it will be looking for the transmission signal.
Unless, you switch to a '98- 2000' 1/2 ton or 3/4 ton pick-up with a manual trans. Then you can run a 904, 727(bolts right up) or a 200R4 or a non-computer controlled 500 or 518, which are the preferred way to go if you want to use the Mopar overdrives.
I was told by a couple at a car show that using a 518 overdrive in their small block a-body slowed the car down 1.5 seconds in the quarter mile. Who knows if they didn't use the right converter etc, but they are no where near as efficient as a 904, 727 or 200R4 and take a lot more power to drive reportedly due to the design of the overdrive being on the tail end of the trans. There are various opinions on this, but they are heavy and BIG!
I've got a nice 4000 mile old 727 with shift kit, 2200 rpm stall converter, deep aluminum pan, lokar cable and new driveshaft (2000 miles) I am letting go for one heck of a package deal.
View attachment 200R4 tunnel surgery.jpg
View attachment Mopar overdrive surgery.jpg