No, I would think you could use whichever one you like. It certainly sounds like you don't need the biggest and baddest, so just a good one is fine.
Even if you found a stock box for a good price it would likely work well for you for years to come. Problem with most of those is that they're actually more expensive when all is said and done, than a brand new box and components.
You could get away with just a lower yoke to adapt the new box to your stock shaft, but at this point I wouldn't scrimp too much. A new collapsible shaft with u-joints at both ends would be a good positive upgrade.
Shipping heavy parts is always an issue, but check around to see who's got good shipping.
As far as WH is concerned, here are the kits and accessories we offer:
http://www.wildhorses4x4.com/category/bronco_Power_Steering_Kits
You'll notice some that are less expensive such as the #2015 for $899, but that would not be advised for your 2.5 lifted EB.
The bolt on kit with all you'd need, including the pressure hose and new collapsible shaft would be this one:
http://www.wildhorses4x4.com/category/bronco_Power_Steering_Kits
It's a quicker steering setup than you have now with your manual, or stock power box through '75, but not too fast. About 4.25 turns lock-to-lock.
I would just get one that bolts right up with no modification to the frame, and don't pay extra for double-beef like a 4x4x2 setup (which is the cat's meow, but overkill in your case) or ram assist or anything like that.
Only thing you'd need additional would be if you had a 351 you'd use the adapter brackets for the pump. Otherwise you'd be good to go.
Paul
