The 1955 Truck Shop Manual describes the non-vented valve cover with a vented filler cap. This seems to be the first year these were used on light-duty truck 235s.
All three of my 1954, 235 engines (1/2 ton manual, 1 ton manual, and 1/2 ton HydraMatic) have the 4 venting slots, the Chevrolet script along the top, and 4 machine screws to hold them to the head.
The 1954 Truck Shop Manual describes the use of 4 hold-down machine scews/bolts; and, the 1954 Engineering Features book/manual shows this new-style valve cover, with Chevrolet script, 4 hold-down bolt/screws, four breathing slots, and the older unvented oil-filler cap.
I do not know if this type of discussion is better than discussing politics - yes, I think it is.
Tim
