My take on the oiling system crossover tube for the small block

Head Oiling Mod

This is a mod that is used with adjustable rocker arms or stamp steel rockers.
Drill into the passage in the lifter valley that feeds the cylinder heads with a 1/8" bit. Be sure you’r e inline with the main oil galley. Tap this hole for a #8 set screw. Now with a 3/32 bit, go thru that hole an drill into the main oil galley. After the block has been cleaned Loc tite the plugs into the outer tapped holes.
The heads will now have full time oiling to the rocker arm shafts.
Before the final cleaning is a good time to tap the oiling hole on the deck so if you go to the magnum heads later you can screw in a plug to block the oil off. The hole is already the right size to be tapped 5/16-18.


A Couple more things on the oil passages

While you are drilling out the main passages, the oil pump passages in the number 5 main cap need to be drilled to ½” also. On the 340 and 318 it is a straight shot but the 360 cap may have a bend in it . Being careful not to go thru the side, drill from both sides of the 360 cap then use a bur to smooth where they join in the middle. Debur the area where the oil pump mounts. Make sure the pump has a flat surface to mount to also.
In the main saddle area remove about 1/4 inch in the place where the oiling passages come together under the bearing shell. Some builders then slot the hole in the bearing or add a second hole next to the first one. Use full groove bearings, in some cases you may have to buy 2 sets and use the upper halves from both to make a full groove set.