Hi John,
I used one from Zip Corvette I bought a few years back and even though their website states it doesn't interchange with original parts, I found that not to be accurate as I was able to reuse my original impeller. The ID of the original impeller was the same as their steel impeller. When you think of it, the shaft has to be the same size in order for the belt pulley and fan space to properly fit snug on the shaft.
I have to rebuild another 67 water pump and this time I'm going to get the kit locally from LI Corvettes.
https://licorvette.com/water_pumps_and_water_pump_rebui.htm They have the '65 396 and '66-'67 427 kits. I am told the kits are the same with the exception for the rear plate retaining hardware. The earlier 396 used screws and the 427 used recessed head hardware. The LI kits don't have the steel impeller so you'll have to reuse yours.
If you have a press handy then you can easily rebuild yours. I used this article as reference and though it mentions setting the hub height to 5 5/8" (for a SB),you'll have to set it to 5 3/4" if you have a BB. Also, some kits have a 2-piece bearing seal and others have a 1-piece seal. The kit I bought had a 1-piece seal and the video link below shows how to install that.
https://www.powernationtv.com/two-minute-tech/2min-434/how-to-rebuild-a-water-pumpMike
