The spacers are available in a variety of thicknesses to accommodate your specific application. Bolt thread is 5/16-24.
UNIVERSAL MECHANICAL COOLING ALUMINUM FAN SPACER 2" GM FORD MOPAR 5/8" PILOT
UNIVERSAL MECHANICAL COOLING BLK ALUMINUM FAN SPACER 1" GM FORD MOPAR 5/8" PILOT
Universal 4 Blade 19in Steel Mechanical Cooling Fan IMCA Racing 5/8" Pilot Black
Allstar 30104 Mechanical Cooling Fan 15in Fan 4 Blade 5/8" Pilot Universal Black