I agree with Will. I think you will like the 200r4. I'm not sure if it is as touchy about the throttle cable setting as the 700r4 but suspect it is. Just find some good instructions and follow them.
The tough part: Be honest with yourself about what the vehicle will be expected to do and chose the rear end gears to suit your needs. My '68 C20 has a 700r4 and 3.54s (350) never lacks power and does 70+ all day. Towing/hauling no problem. No reason your setup won't do the same. 3.73 or 4.11 might be a bit better for the 250. Just take a little off the top and add it to the bottom. Tire size matters too. There are calculators out there that will help. I'd make my choice based on being at the best rpm for MY engine (all mods figured in) in OD at highway speed.
