Opti-Mist
Platinum Member
That is a 1968 3500. It has a split frame loader where each half of the loader frame attaches to the steel radiator shell (hard shell). There is a crossover tube to connect the halves and allow oil to circulate. It looks like the fill plug is on the top of the left loader post and the pump suction line attaches to the bottom of that post, to a removable plate. The filter is attached to the top of that plate. The return line would connect to the right half of the frame. Its been a few decades since I've played with one.