case drill for oil pump?

[Panhead Jim]

1959 harley cases. Bottom end is good. want to go with SS oil pump. have hydraulic lifters. will I need to drill anything to make the ss pump work right? what is the drilling for? I mean what passage does it open, what assembly does it provide oil or drain to? What have other people had success with? My basic problem is, I've got a new Accurate top end, and want it to last, so want more pressure, more volume than the worn, stock pump. Somebody explain, please?

[yard man]

I asked a local shop what the drilling is for and they told me it was just that the mounting patern is different. They werent to sure but thats all they knew at the time.

1959 harley cases. Bottom end is good. want to go with SS oil pump. have hydraulic lifters. will I need to drill anything to make the ss pump work right? what is the drilling for? I mean what passage does it open, what assembly does it provide oil or drain to? What have other people had success with? My basic problem is, I've got a new Accurate top end, and want it to last, so want more pressure, more volume than the worn, stock pump. Somebody explain, please?