Oil pumps?

[Baggy2]

As part of my re-build I thought I would treat my Twink to a new oil pump (just mild road use) . I bought one that said it was for a ford crossflow mostly because of the added convenience of a spin on cartridge rather than the older type. I was about to fit it and then noticed that although the various holes on the mating face were in the same position and matched up with the gasket the actual ducts or oilways in the pump seemed to go to completely different places - at least one looks like a dead end. Its dificult to tell what leads where in the internals of the pump but could I have got hold a pump that shares the same external shape but is quite different internally ? Was my initial assumption that a pump intended for a crossflow would be OK on my twin cam?
Thanks folks
Baggy

[rgh0]

The original pumps had 3 passages to the block - 1.suction, 2.oil supply to engine and 3.relief valve return to the sump. A modern cross flow replacement pump should be interchangeable with the original twin cam pump. I believe some of the replacement designs return the relief valve discharge to the suction line and not back to the sump independently.

cheers
Rohan

[Baggy2]

Thanks Rohan. I'm away from home at present but your answer re return oil makes some sense - I'll be able to check when I get back
Baggy