Since you don't know any history on that pump and it's been sitting, I would, at the very least, change the thrust bearing. They like to let go and do some serious damage. The bearings are cheap compared to the damage it causes if it fails.
motor looks good, what kind of hp/torque are you looking to get out of it? with a olds its critical to get the oil back to the pan, have you done any oil mods? there is plenty of info here and on www.realoldspower.com a easy way is to drill and tap some 3/8" holes in the back of the heads back down to the pan, I used some clear hose so I can see it and it starts to flow around 1500 rpm. also oil restrictors, I don't like the set that most shops sell that just hammer in, I got mine from andy at olds performance products, they thread in. there are a bunch of things you can do to help the oiling system, there is an old hot boat article written by timinator, here on the boards with a bunch of good info, if you can find it its a very good read!
good luck and nice boat.