Been a while since I played with a flathead, but I remember they used to use truck water pumps because the mounts were more suited to a hot rod frame. Also, you have your mounts right up against the water pump, and you would actually have rubber bisquit type mounts in between, which would lower the frame portion of the mount.

Since you are going with this engine you might want to pick up Vern Tardels book on building traditional hot rods. I plan on getting one when I start building a car around the flathead I have stored away. I think it addresses mounts, water pumps, etc.

Don