HELLO,  IM GOING TO TRY TO MAKE THIS QUESTION SIMPLE.  IM GOING TO GET A 350 MOTOR FOR MY 87' JEEP YJ.  ALL I NEED TO KNOW IS WHATS THE BEST TRANS TO GET FOR IT.  IVE BEEN TOLD I CAN GET A TH350 BUT IT WOULD HAVE TO BE FROM A 4X4 TRUCK.  SOMETHING ABOUT THE SHAFT LENGTH.  IVE GOT A CHANCE TO GET LIKE NEW 350 WITH THE TRANS FOR  2200.00.  OR A CHEVY 406, MOTOR WITH EVERYTHING ON IT,  READY TO DROP IN, FOR 1,300. WITH NO TRANS.  NOW I DONT KNOW IF I SHOULD CAUSE I DONT KNOW IF THE TRANS WILL FIT(BECAUSE ITS NOT A 4X4!!  WHAT WILL FIT!!  IM GETTING FRUSTRATED AND IM TRYING TO DO THIS ASAP.  CAN THE TH350 BE BUILT FOR A 4X4?  I KNOW I NEED AN ADAPTER(NOVAK).  SOMEONE PLEASE MAKE THIS SIMPLE FOR ME. MY YJ IS A STICK AND I CHANGING IT TO AN AUTO. TELL EVEYTHING I MIGHT NEED. PLEASE HELP!!  EVERY THOUGHT APPRECIATED, THANK YOU!!!  

I would strongly suggest you use a 700R4. It is a bit longer than a THM350 but it has a much deeper first gear and OD and the really beauty of it is that you can put some real serious axle gears in it and run really strong and still cruise nicely in top gear. Example, a 700R4 with a 5.13 will cruise at a lower RPM in top gear than a 350 or 400 will with 4.10's and have gobs more power in lower gears.Second gear in 700R4/5.13 combo is only about 20% taller overall than first with 350 combo. (first with 700R4/5.13 combo is about 50% deeper than 350 combo) Sometimes 700R4 get a bad rap because people lift truck and install big tires and ride stall on tranny in OD and slow bake tranny and kill it. (if they ran it in "3" with that combo it would lock out OD and be like a THM350 with a deeper first and second gear and it would last a while even with tall gears) You want at least a 700R4 with 30 spline input shaft (late 84/early 85) and 87 on had no more revisions till end and was solid. (87 saw the addition of secondary valve body to improve shift quality)  

I would go with the 700R4, too.  You will need one from a 4x4, though.  The output shaft is shorter, and the tail housing is made to bolt to a transer case, instead of the slip yoke output on a 4x2, as is the case on the 350 turbo.  Shouldn't be hard to find, as Chevy parts are the easiest to find.  

jpatton1493:
I would go with the 700R4, too.  You will need one from a 4x4, though.  The output shaft is shorter, and the tail housing is made to bolt to a transer case, instead of the slip yoke output on a 4x2, as is the case on the 350 turbo.  Shouldn't be hard to find, as Chevy parts are the easiest to find.

The real reason you want one for a 4x4 and not just swap tail shafts is because 4x4 versions of tranny have a much thicker case thickness. They as easy to ID, they has a cast bolt on lower torque converter cover rather than a thin stamped steel one.