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

nm9stheham said
Man that is a bummer. Can you share with us what drill speed you were using, etc? We did 5/16" bits through the 4 passenger side oil passages, so it can be done. But we:

limited speed to 400-500 RPM with a hand held drill

light pressure and very slow

used plain iron oxide bits

used very little lube, if any

pulled out frequently to let the chips clear

we also looked into the holes from time to time to see that the drill was following the original holes.

(Just what you need to hear after the fact LOL)

IMHO, I was reading your earlier posts and was going to comment that I was a bit skeptical that a simple plug was going to seal the coolant from getting into the oil gallery.... unless you put some sort of sealer on it. Seems like a dry plug might seep some coolant.

Seems like a good plan is to figure out if you are going to do these mods up-front and do them first thing... in case something goes awry...

The set screw and expansion plug would have worked for the #1 main to galley repair.
Oil from main saddle could not go up to where the drill bit went out the side.
From the factory you have an expansion plug in the end of the galley keeping it separated from the water passage at the front of the block.

It's the #3 main that one can not get to or alienate from the rest of the system.

The biggest issue was starting the hole STRAIT and parallel to the existing hole.
On the ones I got lined up properly they drilled out easy and you could tell when it broke into the oil galley passage.
Was definite.
If at any time it starts drilling hard or your getting too many shavings coming out it's time to abort the project. LOL