from what i've gathered (getting ready to swap to 200-4r): the 200 takes the same driveshaft as the 2 speed and th350, and you can modify the crossmember, or use a 400 crossmember. i'm sure the lines are a little different, but there may be a way to get them to work with slight mod. the lockup converter needs a power/cutoff switch, a tv cable needs to be hooked up to the throttle exactly right, and the linkage needs to be modified. kits are available for everything you need.
the 700 needs all of the above mods, plus the 400 crossmember will need modified, and the driveshaft will need to be changed to a shorter one, possibly with a different front spline. also, i believe most 700's have a chevy bolt pattern, while all 200s have BOP or universal.
the 700 has a steeper first gear (3.08 versus 2.74) but the 200 has a slightly better overdrive (.67 versus, umm .70 or .71).
