It seems that oil drainback from the heads builds up in the lifter valley. at some point oil returns to the pan by exiting through holes into the timing chain cover or it goes through holes above the cam tunnel. If the front holes are slotted, less oil goes into the crankcase and windage is reduced, but what effect does this have on cam lobe oiling. I know that the con-rod squirt holes are supposed to supply oil to pistons & cam lobes but is that sufficient.
Thanks, Seth
68 AMX 390