Need Help with Power Steering Pump Bracket ID

Both of my 67 Plymouth 273s have that Saginaw pump with different brackets on the cast iron water pump. My pump pulleys are different ( have spokes ), and I suppose there's a difference in pulleys offset.
My add on pulley at crank is about a inch larger diameter than first, alt'/water pump.
I'll guess you have a different engine, aluminum water pump, etc...
I can't say anything bad about that pump though. Very easy to rebuild. Lots of aftermarket caps for Saginaw fit it.