Del ray, All of us are trying to help you and we all have different ideas about how to go about it. Your oil pressure may not be exactly like you would want it but its not all that bad. I personally would not think of pulling the engine back down at this point. I would go to chevrolet and buy some E.O.S.( engine oil supplement) I know someone who has the same situation with a boat with a 400.The E.O.S. helped his oil pressure and it has done well for over 400 hrs so far.Your clearances may not be perfect but You can live with it. Also that distributor bothers me. It wont cost much for you to have another distributor setup on a distributor machine and run no more than 34 total degrees of timing. Just to try it. I would leave the hv pump just as it is . A small block High volume pump just about amounts to a big block pump with a small block pickup. The H V pump has bigger gears and does exactly what it says. produces more volume. As For the cam, I think it's fine but Im not the cam expert. Tomorrow morning, Call Comp Cam Help Line 1-800-999-0853. Tell them everthing about your engine and your car . They can tell you whats what. For the most part I feel my thinking aligns with Denny's first and last post pertaining to oil pumps and oil pressure.I would be much more concerned about the spark knock than than the oil pressure at this point. Again after weighing out everyones input hopefully you can find some good solutions.