[Mr70]

That's a single groove water pump pulley for:
*62 4 cyl w/o p/s
*62 Chevy 6 cyl w/o a/c
*63-65 Chevy 4cyl.w/o 62 amp alt.
*63-65 chevy w/o 62 amp alt. or a/c or p/s
*64-65 chevelle 8 cyl w/o a/c
*65-66 chevy 8 cyl w/o 409-a/c-62amp alt.
*65-66 pass.6cyl. same.
*66 chevy w AIR 6 cyl.
*66 chevy w/62 amp alt.w/o 8 cyl.a/c
*67-68 chevelle 8cyl. w/o a/c or AIR
*67-68 Camaro,Chevy w/o AIR a/c p/s
*67 pass. w/o AIR a/c p/s
*68 chevelle w/pg w/o a/c
*68 Camaro w/TH w/o a/c
*68 All w/TH 350 w/o a/c
*68 Camaro & Chevy w/ Torque drive
Note mentions some of these models may require reinforcement #3720616 with this pulley.