Help with Engine Block Numbers

I'm trying to figure out if my engine came with this car. I have a 68
Dart 4 door 270 with a 273 the numbers on the front of the block under the drivers side head are 22651740 PM 273R. I understand the 273 but what does the rest of it mean are they part of the VIN?

No, the vin number will be on the left side on the bell housing flange on the block or possibly right hand side just above the oil pan rail