[Bruce Meyer]

Originally Posted by kpbrown31

After searching on here, it seems the consensus is to just drill the rear, passenger side plug? And NOT the front plug to lubricate the timing chain. I had some plugs that came with a block and the rear one seems like it was drilled to .030 with an eyeball test, but the front plugs almost look like a 1/16". I just planned to throw the front ones away and replace with standard, non-drilled plugs. Also being mindful of plug depth to avoid oil starvation.

I put a hole in the front driver side plug in my motors. I noticed no difference in oil pressure. More oil on the chain is a good thing.

[Schurkey]

Originally Posted by kpbrown31

After searching on here, it seems the consensus is to just drill the rear, passenger side plug? And NOT the front plug to lubricate the timing chain.

Originally Posted by steve25

The timing chain gets plenty of oil from the passage feeding the fuel pump excentric, so no need to bleed off any more oil pressure with front galley holes.

Originally Posted by Bruce Meyer

I put a hole in the front driver side plug in my motors. I noticed no difference in oil pressure. More oil on the chain is a good thing.

The spurt-hole in the FRONT plugs has NOTHING to do with oiling the timing chain. The chain may get more oil, but it's adequately lubed without the oil gallery plugs getting drilled. Any additional oil on the chain is INCIDENTAL, but not the primary purpose.

The primary purpose of drilling the plugs in the FRONT is to BLEED AIR FROM THE OIL GALLERIES AT STARTUP, so the air in the oil galleries doesn't have to go through the lifters in order to escape. Therefore, the lifters get less air and don't clatter--or at least there's less clatter at startup.