As stated in another comment, the cam has holes in the #2 and 4 IIRC, it's been a while since I had one apart. Like the Big Block series, the oil is metered to the rocker shafts through these holes, only difference is in the BBs it's #4 only IIRC again. I do know for sure other engines go about this in other ways or not at all as in the case of FORD FE's which had no metering at all. Those engine literally flooded the tops and would be real smokers when the guides and seals went bad. I used to make plugs from 5/16" bolts to drop into one of the shaft mount holes each side, which would limit flow and give the benefit of raising oil pressure to the entire engine, mainly crank, from near ZERO to ACCEPTABLE ! Yes I know this is a MOPAR site, said that before, but let me quote an old dear friend whom I worked with long ago, "If it weren't for FORDS and CHEVYs, MOPAR owners wouldn't be able to make a living. And it never hurts to KNOW stuff like that. As for getting the drill going the wrong way, it happens all the time! I had a moment myself more than once, like putting a 440 together and wiring the plug wires as if it were a SB and could not understand why it wouldn't start. Just spin the pump in the right direction and it will prime itself unless it an old REMAN pump like one I install back in 1974 into a FORD FLAT HEAD rebuild, the only way I could get more than 5 PSI was on a cold and I mean COLD start, -15 in January with 40 weight. I knew the pump was working because it would make pressure cold so it had to be moving oil warmed up, it just wouldn't move it with any pressure. That engine was still running 20 yrs later when the owner died in his late 90's. On the other hand, I had a 318 with the stamped steel oil filter cover that when I put a HVHP pump in would blow out the gasket between the block and cover no matter what. I wasn't going to pull the pump out for any reason, not with the engine in a VAN, so I simply ordered one of the right angle cast filter adapters which has always made so much more sense from the start than that space limiting POS stamped plate. I will never figure why MOPAR did such a stupid thing as that, NONE of the other Manufactures did anything like that until VW came along with a PLASTIC POS that is even STUPIDER, did I just say that? For these reasons I no longer make a living doing this stuff, I quit! I have no more real MOPARs left but would like to.