Just bought some used Edelbrock RPM 340 heads... for my Magnum

the "t"-ing off the oil pressure port sounds doable. how about a fitting straight out the back of the valve cover for the line to attach to? a nut or flange on the inside of the valve cover with a thick seal and a thinner seal, washer and nut on the outside to keep the seepage down. OR, tap the inside of the rocker shaft and thread a fitting in from the outside with the seals only on the outside. watch out for 90 degree fittings, it is like adding length to the hose.