on my LA engine the passenger side top cam retainer bolt passes through to the valley. That is the one that should have a hole in the bolt. I think the idea is that the oil drips out from that hole and runs onto the tab and onto the chain. I know I forgot to put a drilled bolt in there and ran no oil slinger and my chain was smoked in 5000 miles. I just recently put it back together and corrected those issues.
I though of drilling the end plug of the valley, just wondered what others have had success with.
Both top bolt holes are blind, no oil going to come from there without modifications. The bottom bolt holes go through to the crankcase area.
Those 2 large holes to the valley are not at the bottom of the valley so how much oil will pass through there at 2500-2800 RPM on the freeway driving? I would imagine that’s why they put those holes there. I also think that’s why they added the drip trough in the late 70’s, it didn’t oil the chain very well.
