h212 would be august 21 1992 "h" is The 8th letter of the alfebet, 21 is 21st day of the month, 2 is for 92.
Not shure what the other number you posted is. Where was it located? The "660 block 6.2s have the cast date on them on the bellhousing flange drivers side like this pic
Not shure what the other number you posted is. Where was it located? The "660 block 6.2s have the cast date on them on the bellhousing flange drivers side like this pic