Since there are 8, there is a pretty good chance they are out of some sort of V-8. Was there any kind of equipment setting around at the sale?
The pin diameter is too small from a 5.9 or 6.7 Cummins. They do not have a steel top-ring land so they are not a high duty cycle street use setup, but they are cast so they don't have the strength of a billet piston.
I'd say you've got a nice set of paper weights as far as usage in a Cummins engine. As for the real application, probably diesel with an offset injector based on the bowl design. Still not sure why it lacks a steel upper ring land.