Hey guys/gals. I've been in the hobby for a few years and have built my share of 360/390/401 and have wrote about one mod that not to many of you out there seems to know about. It's about the oil gallery going from the lifter oil journal to the mains. I use a 5/16 drill bit about 10 inches long to clean this journal. Go from the main journal into the lifter journal. have all oil plugs off at the time to observe the drill  bit tip doesn't go too far. you will get metal out since AMC didn't all ways go all the way through to the lifter gallery. But most of you know about this. What most dont know and I found this out from experiance is the cam bearings can really restrict flow to the mains more then anything else. without the cam bearings installed the flow from the lifter gallery to the mains is 100%. just a open 5/16 hole but once the cam bearings are installed the hole closes by 25% or more and in my opinion can be a concern expecially if running a heavy weight oil. My fix for this concern is to chamfer the back side of the cam bearing where the oil hole is. not enought to make the cam bearing hole bigger you don't want that. just enought to not restict the flow to the mains. I use a 5/16 rat file and put the bearing in a vise with rubber protectors.  I then mark the center piont on the bearing and the block to make sure that the cam bearings get centered while installing.  once installed the restriction is down to maybe 5%.  On another note oils  another post maybe.