oil pump headaches

[LilBill]

While gathering parts for my 67 generator motor i am having a lot of confusion over what oil pumps will work. My "what fits what" book states there are 5 different harley pumps. 48-67, 68-72, early 73, mid 73 and late 73 thru 80. So from that i would think that i need the 48-67 iron pump.
BUT
Looking in various catalogs i see pumps listed as fitting 54-72 and another as fitting 36-72.
SO
Can I use the aluminum 68-72 pump on a 67 motor ?
Will any of the post 72 pumps work if modified in some way ?
My head hurts 

[MMOCGuy]

I don't remember what year the transition was but, the later pumps will work on older engines. They require that a new hole be drilled in the case. There are jigs available so that the hole is drilled correctly and the jigs are available from all of the suppliers J&P, Jireh, etc.).

I can't tell you much more than this but I'm sure some of the others will chime in soon.

Hope this helps.

Norm.

[Dawgtired]

LilBill,
This may help ya, http://www.sscycle.com/modules/instruction/uploads/51-1041.pdf
Dawg