Old School vs Magnum on 86 Dodge W100

Pushrod oiling plus external oiling tee'd off the oil pressure sender port on the block. You might remember my build from a couple years ago I think you were active in the build thread, I bought used open-chamber Edelbrocks and had them drilled to supply oil from the back of the head through the rear-most rocker shaft bolt. I actually had to weld up and re-drill smaller holes in the rocker bolts because it was pumping way too much oil up top and my hot oil pressure was quite low but since then it's worked great. Gives me some extra peace of mind with the constant oil flow since I'm running an almost-.550"-lift hydraulic roller cam with factory stamped LA rockers and it sees a lot of street use at idle and low RPMs.
OK, that was the setup I was thinking of... could not connect you to it! The big point to the OP is the LA318 heads on the Magnum block need an oiling path added. Since this is a standard truck use, and a stock cam, the ports ought be adequate. But the open chambers are not going to be as good for compression... a step backwards unless you mill them down some IMHO.