Without seeing the engine and casting numbers it is pretty hard to tellyou what you have there. That is not a number location and the original location appears to be numberless, assuming we are looking at the area the water pump bolts on.....Probably was milled and the original numbers are gone.

I can't tell you the significance of the numbers in your pic other than someone did it wrong and restamped one digit. The font looks older but whether it is a Willys font I can't say.

The casting number on the right side of the block is 641087-L-W10A. There is no engine number stamped on the right side of the block. The block has the small flange at the rear. The engine number was not visible on the water pump boss at the top front of the block when I bought it, but in the right light I could almost convince myself that there was a very faint hint of a number there. The over-stamp of the 8 and 7 is very close to where the top diagonal edge of the water pump casting would be if it was installed at the time the number was stamped. If I had to guess, I'd say that a previous owner stamped the number himself after it was machined off the top of the block. There would not have been enough room for the entire engine number so he omitted the prefix, then ran out of room anyway. So, if my WAG is right, and if it is a 3A block, that would give us a 3J08787 engine number. My vehicle serial number is 46284, well out of the skew range. So, maybe a WAG is just a WAG. Here's a couple more pics.