I put a 454 in my 85 Suburban and it was apparently too much motor for the stock 700 R4 trans., so here is my question, what would I have to do to swap out the 700 R4 with a turbo 400? Would I have to change drive lines, are the trannys different length, and will my transfer case on the 700 R4 bolt on the turbo 400 because my transfer case is fine. Any help would be appreciated.
Or would I be better off rebuilding the 700R4 and having it beefed up to handle the power and torque of the 454?

the cool thing with chevies os many combintations of trannys and tcases bolt together.

i havent done it for sure. i had th350 in my blazer and swapped it for manual 4 speed sm465. i didnt have to change drivelines or anything.

theres along adapter between the tranny and t-case thats makes up the difrence.

i could be wrong but the autos may be dang near the same lenght

youtube it im sure someones most likly done it and made a vid on it

i did the swap after blowing out a couple of 700r4s, went to sm465 the adapter works that comes on the 700 didnt chage drivlines just u-joints. the next thing will be the ratio on the axels, 70 mph wasnt in reach. ended up blowing 2 rear axels with a little 0.060 350. played a little hard. atomatics are great for the road but you can't beat the control of a standard or direct power.
i have a 90 or 91 its been to long since i had it on the road, axels are hard to find here.