The 727 in my truck is going ('70 383/727 2wd), it still behaves well most of the time but loaded up with motorcycles it has been slipping up hill on the freeway. I'm sure the bands and clutches are just about worn out. It would down shift to 2nd then try to shift back to 3rd and get hung up in between.
Super Cheap option #1:
I've got a possible replacement but it is a 727 out of Scout with a D20 transfer case still bolted on, no idea what the bell housing bolt pattern would be off a IH 345. Could I swap the tail housings and bolt it right up (yeah right). Or should I swap the guts from one tranny to the other?

Sort of Cheap Option #2
Should I become a truly manly man using common hand tools in my garage and attempt to rebuild the original 727 myself?
No so Cheap option #3
Get a dam overdrive finally. The only thing I don’t like about the truck is the missing OD. I know there isn’t a solution for mating a 383RB with an OD tranny but it sure would be nice. Any new developments mounting an OD or a modern manaul with a double OD like a Tremac T56? Looking for junk yard specials here.