Chevy c-10 crank pulley

[tdairy]

own a 1972 chevy c-10 short bed with a 250 cid. 3 on column, no ac or power steering. single belt deal but I have lost the crank pulley somehow. my harmonic balancer appx 4.5 inches is in place but the pulley that bolted to it has some how come loose. pulley should come back over the balancer appx 1 inch as I remember. can not find one or the proper part number. I have seen a set up with balancer and pulley as one but this was not the case with this truck. really enjoy driving this old truck but cant til I fix this deal. any help would greatly be appreciated.