340 casting production
As Far As 340 Warranty Blks They Still Had Date Codes And Casting #'s, The ''no Numbers'' Were Refering To Serial Numbers Stamped In Boss In Blk Pass Side Right Above Oil Pan Rail,and The Dealers Were Supposed To Stamp Them, Not Many Dealers Did, Have Personally Seen 2 Of These Blks, If U Have One With No Casting Date Or Casting Numbers [ Extruded Numbers] Then They Have Either Been Taken Off Or Is Some Type Aftermarket Blk, All Factory Blks Have Casting And Date They Were Manufactured, This Came From A Dealer Who Dealt In Mopars For 35 Yrs, And All Blks Were To Be 'stamped' At Time Of Installation To That Specific Car Which Is Why The Last 6[i Believe] Digits Were To Match Vin Of That Car.