There were some blocks cast in 1974, would have to dig some old Chrysler Performance Books up to remember if there were any long blocks with 1974 Casting or short blocks. I remember Mancini in around 1978 got a few short block Hemis and had them for sale but I dont remember the casting dates on the blocks. The stamping on the bottom of the pan rail I have never come across those markings on another block that was cast in 72-74.The Markings on that pan rail tell the story of the block,.when it was machined, when it was assembled and what number it was assembled at and what year is might of gone into. Since 1974 and up there were no Hemi Vehicles I know of being built the block would be an over the counter something. Top Fuel, Funny Car did not run this block at this time would of been a Keith Black likely for them.