It's been a decade since a had a C2 style pump. Now I've got a Saginaw and needed new lines when I did that.
I'm pretty sure 2qts is enough to fill the box, the pump, the two lines and the cooling loop.
Gary's Hydroboost would obviously take more. 🙄
Just be sure to keep the reservoir full, start the truck and work the wheels lock to lock a few times until you don't get any more foam at the pump return before you try to drive it.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.