'89 roller-cam LA 360 w/Magnum heads - new roller lifters not pumping up

The hollow bolt DOES NOT go into a pressurized oil galley.....its purpose is to alow "drainback" oil from the lifter valley to drain onto the little sheet metal tab, thus directing oil to the chain. The driver side oil galley is fed from a small (9/32 IIRC) hole up from the front main. The proper place to put the hole you drilled would be the passenger side plug, as you have a lot more volume of oil there due to the fact its the FIRST thing oiled, and is supplied by a 1/2 oil galley. That would be a negligible drain on the system. As it is now, your supplying 8 lifter bores AND your new hole with a much smaller passage, thus putting a lot more "leakage" percentage wise..... into the mix. Even the mopar engine bible mentions a small .020 hole in the plate on the passenger side..... Just food for thought.