Does anyone know the correct valve cover oil filler cap for a 340. This would be for a late build 1971 corporate blue engine.
I have seen one with the center rivet with an "S" stamped on it, and another cap that has E/F on the ears. Thank you.

Unsure about the blue painted engines if they changed anything by then.

Here is an older multi-page thread about correct 340 engine details that you may or may not have already seen. Some good stuff inside even though most of it is geared towards the 70-71 engines that came painted orange..

https://board.moparts.org/ubbthread...lly-anal-long-winded-o-e-340-thread.html