Kinda curious what these little numbers signify. I guess as long as it doesn't have a 53 I am ok, but I am just wondering what everybody else's engine blocks have cast into them number wise, might be kinda interesting to see.

driver's side

pass side

Those are just engine block numbers. Can't really look them up. The data plate on the side of the timing case is all you need to be worried about. As far as 53 block, check this out http://www.stamey.info/Truck/Cummins53BlockFAQ.htm

my 99 has a 53 block...180k and no cracks, and still on the original VP44(from what i can tell)