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

Alex5280 said

^ I was going to...I thought that was part of the Guitar Jones instructions, But I think you are right Rumble...don't need to drill that passage out.

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Yes drill it 1/2 inch.
The bottom of the passage is 5/8 or more. The passage above the plug is below half inch that's the part you are drilling out. You are not knocking the shoulder out of it.