Drilling oil galleries and oil return holes?

ValiantOne said

Now I am confused again about the passages to the mains. I thought the stepped holes I am supposed to drill run from the main bearings to the cam bearing area (not the lifter gallery). Do I have this wrong. There are three holes that lead down to the mains. I thought the stepped hole went straight up to the cam bearing area. The block is at the machine shop so I can't go out and look.

When you say the "front bearing holes need the most attention" does that mean mains 1&2? Or does it even matter if I do all of them?

Thanks,

CE

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Sorry to not be clear. I was thinking you are drilling out the holes from each main up to the passenger side lifter gallery. Those are the oil supply passages from the passenger side lifter gallery INTO the main, rod, and cam bearings.

The #1 main hole from the passenger side lifter gallery supplies both the #1 main and the #1 rod, but also there is another passage from the #1 main saddle back up to the driver's side oil gallery. All the driver's side lifter gallery oil goes through that area so adds a fair amount of flow into the #1 main. So I drill out both passages from the #1 to each lifter gallery.