A differnt option would be to use the drive parts from P&D Hobbies. Basically these are the duplicates of the old Weaver Single motor drives. Pat at P&D has had new gears and sprockets made to replace the originals. He still had a bunch of gearboxes and towers.
I repowered an A-B set with a torn up fibre drive gear in one a few years ago. It became the best running of the two sets my buddy had and pulled better with less weight.
Pat could probably fix you up with all the parts possible including new sideframes with 8 wheel pickup.