Because the L block is cast differently than earlier blocks in order to have the piston cooling oil squirters, there is also some differences in the machining processes performed.

I examined the oil passages throughout the block casting to see if there were any areas of restriction or constriction due to casting flash or residue. I did not find any problems with the cast passages.

What I did find was three places where the drilling of holes to connect to the cast-in passages were not quite as aligned, or centered, as I would have preferred to see. The offsets of the drillings created restrictions to good flow.

The first restricted drilling/cast passage intersection is where the transfer pipe oil passage in the block comes up to meet the main feed passage over to the oil filter boss.

The second restriction is where the hole was drilled into that main feed passage from inside the oil filter boss.

The third restriction was under the oil filter boss where the oil exits the oil filter and goes into the block to go to the main gallery feed for the main bearings, the oil squirters, the oil pressure switch, and the supply passage up to the cylinder head to lube the cam bearings.