I think I will be trying to do the same thing for my dad. However, I will be using an 89 as my donor truck. If you hadn't cut the floor, would your 55 body sit down on the frame. I'm doing my swap to surprise my dad, so I don't want to cut his truck up to make it work. But I do want to make it driveable...practically.
I started my own thread elsewhere in the forum...not tryin to steal your thread
if you could let me know how the fitment was.
Thanks