It is a milling machine. We centered the intake bore to the bit, then bolted the spacer, with the gaskets sandwiched in between, to the intake. Then bored right through everything.That's a neat way to do it....if I'm seeing it correctly.
Mada a jig out of the spacer so it (the bit) doesn't wonder in the intake...cool!
Did you "jig up" to drill the spacer?
Just used a normal drill press or do you have a milling machine?
This build is great, awesome the boy is getting his hands dirty and learning some great skills.