[lindstromjd]

Well, first, what does the transmission oil pan look like? If it looks like it's got a corner cut out of it, then it's a TH350. If it's a big rectangle, then it's a 700r4. Never heard of a non-overdrive 700r4, btw.

You will not need to change anything on your truck to install the 700r4 except for the transmission cross member. And that's as easy as moving it back a few inches and drilling some holes in the frame. Some trucks even have the holes already in them. The driveshaft SHOULD be the same length. But, it depends on what tail shaft you have on the TH350. If it's a short shaft, you'll need a longer DS. If it's a "standard" 6 inch shaft, it will be plug-and-play swap. If it's the long shaft 9 inch, then you'll need a shorter shaft. Most trucks came with a standard shaft TH350.

The steering column works fine; you'll just have an extra gear down below "1" that is your actual 1st gear. All the shifter linkage hooks up, and the shifter detent has the same spacing between gears. No need to worry about that.

As far as the lockout torque converter... Are there any junkyards close to you? You could scavenge all the parts you need for that from a 3rd generation Camaro or Firebird. Basically you need a switch for your brakes that supplies constant power to one of the terminals on the 700r4. When you push the brakes, it should take power away, and that controls your lockout. It's the simple way of doing it, and makes it so it only locks out in 4th gear.

The TV cable is the tricky part. Gotta make sure it's set up perfectly, or you'll blow the transmission quick fast and in a hurry. Bowtieoverdrives is a great source for all this, too.