Squeaking Sound Coming from 225 /6

youll find the pressure sender at end of oil pump right under oil filter. You can T it and run the gauge and a sender or just replace with sender. Slants will almost idle without oil (seen it on a Slick-50 demo, no pan!) but I would get the pressure tested ASAP.

My 64 has the sender in the block on the passenger's side toward the rear.