A C7 pulley (at least anything stamped C7 on the pulley)
will have an indexing lip and be 3 bolt. I believe that all
'70-up 302's are the 4 bolt crank pulley and no lip, just a
hole that lines up with a raised area on the harmonic balancer.
guys any pulley pre 69 is a 3 bolt pulley meaning it uses three bolts to hold it to the balancer and even then 69 pulleys differ from pre 69 pulleys in how it indexes to the balancer. 70 and up pulleys use 4 bolts to the balancer and do not interchange with 69 and earlier pulleys because of this.