Alternative SB waterpump
I built a short nosed pump, aftermarket bearing and a wp pulley from a 70+ w/ AC. It bought me an additional 1.188 in radiator clearance.
I went with that number based on my desire to use a factory pulley vs making a custom one, but that's about as short as you can really go.
Short nose water pump for electric fan clearance
Inspiration from here
How to: Short Nose Water Pump