On 390 and 428 engines there is a blower motor guard to protect it during decking. In removing the blower guard, I found a tiny (3/8 in.) rubber piece under one of the legs of the guard -pic attached. On my 1968 Dearborn car there was little sound deadener making it easier to spot. The only reason I can surmise is that it was added as an assembly aid to make it easier to install the two Phillips head screws. Once the guard is on, it is not visible. Any other ideas?