For the alternator pulley, try speedway they should have it for you:
https://www.speedwaymotors.com/

The thickness of the adaptor plate for the water pump is compensated for by removing the backing plate off the water pump.

Put a add wanted in the stovebolt here for the balancer, make sure you get a 52 and older one, they have the 5/8" pulley

By the looks of your balancer and alternator setup, I would leave no rock unturned on your truck, check it all out, somebody has done some pretty bad work there. I would do it anyway, that way you know it is done correctly.

Steve

Last edited by sstock; 06/10/2019 4:04 AM.
1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration