For a 250?
Any Chevy truck, Camaro, Nova, full size Chevy car, Olds such as the Omega, Pontiac such as the Ventura or any GM car with a 250 with the same head you have and not the later integral head.
When you find one, check out the pulleys because they will probably be different than yours. The alternator bracket will be part of the pump bracket, so you have to see if it shares a belt and/or if its pulley is different than your alt pulley.