So why is it strange to have six bolt wheels? Everything underneath looks factory. If this dump truck was modified ( cab swap, etc ) it was long ago. Original radiator, PTO drive line looks untouched, wiring, brake lines, etc. all OEM appearing. Once I get it out of the weeds I'll do more digging. It has a canister type oil filter that uses an element instead of the common screw on filter. I had to laugh because I was told it was a 1977 f600 with a 318.