Please help this noob figure out this perplexing query, which engine spins faster at 3000 RPM's a diesel or a gasser? I was wondering this since diesels are so much slower than gasser so wouldn't the diesel spin slower at 3000 RPM's.
I was told by a very intelligent mechanic that gassers spin faster at 3000 RPM's than diesels.
Also I bought an oil cap from the dealer but they gave me the wrong one. Instead of OIL it says 710.

I'm upset at the dealer.