Must be one rare sombeech

Any 4 inch bore sbc 4 bolt main from 1969 and up can be used to make a 4 bolt 327, just need a 3.25 stroke crank & the correct pin height piston & you have a 4 bolt 327. 1969 z28 302 inch engines were the first production sbc blocks, after that a train load of 350 inch blocks were made with 4 bolt mains. 1969 was the last year for 327, large journal blocks began in 1968. All this mix & match stuff could be obtained from Chevy parts counters or junk yards if you know what to look for.
Steve