Welcome,Browndog! I have a '55 2nd-series 6500,with a 261. It doesn't have an oil filter,either. I MAY be mistaken,but i think the oil is filtered through the oil-bath air breather,on "our' engines,whether they are 216,235,or 261's. I WAS thinking about installing a remote oil filter on my truck,but got talked out of the idea,by a company that SELLS the kits! They told me that the truck "ran just fine for almost 60 years,so why change it now"? That's a GOOD point,since installing a kit requires some drilling/tapping,which should only be done,if the engine is completely dis-assembled,to ensure removal of all metal shavings. Drilling/tapping the block for the fittings on an engine still in the truck,would also be difficult,due to the angle needed to install the fittings correctly,into the oil galleys. My opinion. Hope this helps.
