"See that it has a normal oil filter in the normal location."
What, and where, would that be?

1956 256 V8 Truck Engine Specs
A full-flow filtration system was standard-equipment

It looks like that oil filter was optional equipment on 1955-2nd 265 truck engine?
Was the 1955-2nd oil filter a by-pass filter or a full-flow filter?

Can anyone post a better image of that full-flow filter attached to a 1956 265 block (or, the 1955-2nd oil filter)?