The oil fill cap position has more to do with the type of air filter the negine was originally equipped with than any magic wand to identify the engine, plus the valve covers will swap on any engine with the 4 valve cover screws around the perimeter. Casting numbers are hard to swap unless somebody is really good with a cutoff wheel and a welder!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!