So what we see in the pic provided looks like OEM 273. That would be a cast iron water pump, rubber balancer like a/c pulley, and a little tensioner for that single a/c belt.
Depending on what year model the crate engine is... Its highly possible that none of that setup will work. If the crate engine is a later model LA with aluminum water pump, you may as well seek all those pulleys and accessory brackets for that belt arrangement, ( matched pair of belts on alt' and a/c compumper ).
