Ya might wanna get the pulley first and installed then run a tape measure around the pulleys to be sure,
33" is a close length on most, but vary depending on pulley size and model involved.
-----and close only counts on horse shoes and hand grenades.
Some enterprising fellers go to tsc or hwd store and get several lengths then return the incorrect ones.
Do remember to take in account there is quit a bit of belt adjustment on them.