Can you replace rod bearings with engine still in car?

Yep high vol pump and stock oil pan arent a good combo,as the pump can suck the pan dry. You need to at least baffle the stock pan for a hi volume pump and better if there is increased capacity in the pan.

Really good idea on the timing chain as well. 360 tc is a long one.

Cover the rod bolt ends with some vacuum hose for a little protection against nicks etc while you work the bearings in place.