Question? At what point should a larger pickup tube be used?
Also, how much of a restriction is the hole in the oil pump?
I guess this leads to, how much better is an external line connected to the pump cover?

FWIW, both of my 400 and 440 stroker engines have 1/2" pickups. I'm just curious if they are really needed? My Jensen project 440 stroker (505") should be about 600 HP, and I have not decided which size pickup to use?
I picked up one of the 440 Source oil pumps (on closeout sale) that have the connections for the remote oil filter, and also an inlet for external oiling. I am thinking of plugging the external inlet so it will pull from the block pickup as normal. I really just wanted the remote filter fittings as that is how the Jensen is configured originally and I'm not sure what condition the original pump is in.