PS Steering Box Interchange?

[AusTruck]

Do the later, o-ring style power steering boxes fit directly (as in bolt-up, no cutting or modifying) into an earlier truck?

Mine is a 69 C-10 with factory PS. I've got the late model hydroboost setup that uses the metric o-ring style hoses. Rather than make up some kind of adapter or crossover hose, I was wondering if I could just swap out the steering box for a late model one and be done with it. The 69 doesn't leak, and feels ok for what little I've driven it, but its got to have a zilllion miles on it. New boxes aren't that expensive at the scrap yards, what with all the Cash For Clunkers vehicles that were turned in.

I know I'll have to change out the PS pump too, or just see if I can get the little fitting in the back of the pump to budge and replace it with a late model o-ring fitting. Given how tight those fittings are, and PS pumps are pretty common at the yards, it might be easier in the long run to just replace the pump. I know about getting the special PS pulley puller that makes it a bunch easier to replace the pump.

BTW, what year was the changeover to the o-ring style hoses?

Thanks to all on a great board!