GEC52,
What you have is the stock valve cover that had "breathing slots" in the valve cover. These slots and the block draft tube allowed water vapor and other vapors to exit the engine (and prevented build-up of "air" pressure inside the engine. The oil filler cap on these engines were not vented. A side benefit of these slots was that oil could also exit the engine and then coat the valve cover and other engine compartment metal parts, thus acting as a rust deterent :rolleyes: .
Valve covers with slots were used on 216 and 235 engines up to at least 1954.
In case your are interested, pre-'54 valve covers on trucks engines had 2 hold-down bolts in the top. '54 and later valve covers had 4 hold-down machine screws on the side. I do not know what year the 235/261 truck engine valve covers stopped having the breathing slots (my 1960 261 has no slots).
Tim
