my 1st 340....yea

Yeah, I never paid attention to timing covers. I never knew anything but the bolt on tab or 70 and up with the aluminum water pump. Most of my personal cars were 67 down except my 68 and that had a 383.
like a lot of folks i found out about it quite by accident... meaning a weekend thrash session on a work vehicle to swap a 70's 318 with rod knock so bad you'd think the devil was at the door for a pre 70 318 that i had laying about. frustration and hilarity ensued.

trying to remove the timing cover i was using a long flat punch and with what i thought was a light blow from the hammer, poked a hole directly thru the top of it.

and thus, a pull at an errant string of a sweater... or how to turn a friday night and easy saturday job into buttoning it up at 3am monday morning.