602 Block Heater Location
 

Looks like a nice day, so I thought I might hook up my block heater cord to my 91 300D. From reading various threads, I know the general location (passenger side of block, a little ways up). Looking from underneath, I see a black cap, perhaps an inch in diameter, facing sideways but angled slightly downward. Is that it? If not, can someone tell me a little more precisely where to find it? Thanks.

That was it.