I'm building a 421 now 428 pontiac engine, code 35B with 4 bolt mains. There are two oil passages that lead from #2 and #4 cam bearing journals to the deck surfaces. The heads are 6X. With the current combination of heads and block the passages would be open to the lifter valley. My question is, Should I plug these passages or leave them open? I'm concerned they may cause a loss in oil pressure then again they may be there to bleed off excess pressure. TIA
Mark