Call me crazy!! putting a 440 in a 90 Suburban

Yes there are better ways/engines i could use and so on but i have a motor home with a 440 with the 727 with only 13000 orginal miles thats runs and drives great. But... i have a 90 Surbaban thats my baby but the tbi 350 is hammering. i could put another 350 in it for about $600, but i thought i b different and try this.
 Now i want to keep the newer 700r4 (which yes i know they are weak) but i want to keep the O/D. I know im gonna need an adapter plate, different bellhousing, flex plate, figure motor mounts, exhaust and the torque converter the TCI that i found said that motor has to internally balanced? anyone have anyadvice