check this out...
3856223 396 65-66 Forged Steel ALL -
3856223 396 67-69 Forged Steel Chevelle, Camaro Hi Perf.
3856223 402 70-71 Forged Steel - -
http://www.backyardautomotive.com/ch...t_casting.html
Or Here...
http://www.mortec.com/cranks.htm
BBC TWO PIECE REAR MAIN OIL SEALS
3.76" STROKE used on '65-'90 Mark IV 366T, 396, 402, 427 or 427T
3856223....396...forged