I shouldn't tell you this . . .

Jerry Branch ironheads have a small number stamped on the bottom near the intake port.  This helped identify your heads when you sent them to be ported and flowed.  At swap meets, I find myself looking for these numbers - even before looking at the ports - or what the heads fit.  I've never found a set yet . . . and I've looked at hundreds of heads.  If you ever see the beautiful porting on a set of these, you'll say - Wow !