[greg64]

Howdy rizick. I've actually gone both ways on the tranny conversion over the years. Going to auto was by far easier. Okay, here's what I know:
1) Go for the overdrive now (700R4). You'll thank yourself later.
2) Ring gears come in two different sizes and bolt patterns for the torque converter. The larger has 168 teeth and the smaller 153. I'm not sure which bolt pattern the torque converter for the 700R4 uses, but many of these ring gears are drilled for both patterns.
3) Make SURE that the bolts that hold the ring gear to the torque converter aren't bottoming out against the converter. I had this happen, and it led to a damn annoying vibration that took a year (!!!) to figure out.
4) A floor shift (B&M, Lokar, etc.) will be easier to couple up than any column shifter. But of course, both are possible.
5) The 700R4 uses a TV cable that HAS to be adjusted properly. It's not just a kickdown cable like the TH350 uses and if not adjusted properly can fry the trans.
6) Install a supplemental tranny cooler, as well as the in-rad cooler. When towing or climbing big hills, the rad cooler alone doesn't cut it. And, make sure the order is out of the tranny, to the rad cooler, to the aux cooler, back to the tranny.
7) Different starters are used depending on how many teeth are on the ring gear. 153 tooth RGs use a starter where the two bolts are directly across from each other (perpendicular to the crank). 168 tooth RGs use two bolts that are staggered.
8) You will likely need a new driveshaft made, but this is a good opportunity to get a freshly balanced shaft with new U-joints. Take your old shaft to the shop because they may be able to use part of it, and it will FOR SURE tell them what U-joint you have on your differential (I've had past problems with this).

I'll probably think of some more things that I'll add to this post.