340 R vin decoding

crackedback said
6/16/71 is the casting date of your block.
3744 is the build date 10/28/71
0128 is the unit built that day

Happen to have the vin on it. pass side just below a drain hole and above pan rail.

And it IS NOT a 6 pack block...

Hi Crackedback, just wondering what or how you decoded
the build date and unit number? do you have a chart or sheet
you could post or would be willing to share? Thanks either way.
Wheels.