The most reasonably priced component used on the V6 4.3 Yems 1990 Engine Belts - Pulleys is the Wshr,flt,sae7/16".
The Yamaha BELTS - PULLEYS has fourteen products enlisted in the schematic.
This Pulley,circ Wt Pmp is the most expensive of the items that make up this Belts - Pulleys assembly.