Clutch style fan?
Fan blades used on the fan clutches are pretty much universal. The choice of blade may be deterimed by the space available. Generally speaking a V8 in an "A" body requires an 18 inch diameter not having a lot of pitch to the blades, because of the limited space between the pullys and the radiator.
FYI There are two differant types of fan clutches; themostatic and torque-limiting (also called centrifical). Use only the thermostatic type, it is controled by the temperature of the air coming through the radiator. The torque limiting is controled by engine RPMs only.