Need some help decoding 833 PLEASE...

the numbers on the retainer and tail are casting numbers, helps identify the 4 different retainers and approx. 4 different tails, covering a range of years. the 4B297590 is the last 8 of the vin, 4 is 1974, B is the Hamtramck plant. 4578 is date based on a 10,000 day calender, so Feb./?/1974