Can I put BBP drums on my 69 ?

Any big bolt pattern drum set up would require a spindle change too. If you're changing spindles you might as well just go to '73+ disks. All the same things would be needed- new spindles, new lower ball joints, and either LBJ UCA's or the tapered adaptors because all the BBP drum spindles used the larger ball joints. Like the SBP the small upper ball joints were an A-body thing.