small block Edelbrock water pump experiences

I picked up a used Edelbrock water pump from a Mopar swap meet a while back. I'm finally getting around to installing it on my 340 stroker project in my '67 Dart (never been run yet). The problem is, the height of the various bolt holes does not match a factory style pump ('70 & up with passenger side lower outlet, or is it '69 & up?). Thus, brackets such as the alternator or PS are not spaced correctly from the face of the block/head.

For instance, the two holes for the alternator brackets are about 1 9/16 (1.560) tall on the Edelbrock pump, but 1 11/16 (1.700) on the factory pump (measured from the pump mounting surface to the top of the bolt hole). The Edelbrock catalog says all factory brackets will fit. I bought the pump from a guy that said it came from a circle track car. I'm wondering if they machined the pump or if it comes this way. All of the mounting holes on the Edelbrock pump are about 1 9/16 tall, except for the top center hole. The factory pump has several at 1 11/16 (1.700), a couple at 1 19/32 (1.600), and the center hole (which is about 1 inch tall on both). My measurements may not be exact, but it's obvious the two pumps differ in this respect.

Sure, I can space it out with washers/shims, but I was just wondering if that is the way is supposed to be. Let me know if you have any experience with stock brackets and this pump. Thanks!