Mystery vibration at 25 mph can't be diagnosed. It's not the front end!
I found the correct 5 leaf springs from classicindustries.
…for $450, it looks like. Ye gods. That's why you can't afford stuff! It's been awhile since I was in the market for Springs, but I think that price is way, far out of line, and that's because Classic Industries is not the smart place to go buy springs (or much of anything else). If you had posted on here and asked "Where should I buy springs for my car?", we would've pointed you
here and
here. Instead, what you did was Ready...
FIRE!!!!...aim. And that's what it sounds like you're planning to do with your driveshaft. And although numerous people have spoon-fed you diagnostic procedures and other helpful information, you claim to be confused, want to know where to buy a reconditioned B&T, etc.
I repeat myself: You aren't following the good, clear, simple advice you're being given, so I give up. ¯\_(ツ)_/¯
