[Project1970]

Hmm. I've done a little more reading and it looks like the '78 box may be the one I'm looking for:

*Power steering hoses are the same between 1976 and 1978 - still flared fittings, so the '78 is not metric
*Pitman arm is the same between 1976 and 1978 - so I won't need to swap that around

But, the steering gear part number is different between the two - the '68-'76 box is listed as 7501, while the '78 box is 7512.

Part of my worry with going with the '76 box - I'll be getting a reman - is that since they use the same part number, it seems like I'd run a chance of getting another 4.5 turn lock-to-lock box from a '72 or older truck.