Going to detail my engine bay so I'd like to preserve all the factory markings. Apparently, the guy who wrote the numbers on my truck was having a bad day, was a sloppy writer, didn't give a s#it, or all of the above, because I can't make heads or tails of his doodling.
The truck in question is a 1972 C10 Deluxe. First pic is on the drivers side upper firewall area. Looks like "740 BLK" or "940 BLK". It gets a little more confusing on the passenger side forward inner fender (just outboard of the battery box. Is it "43"? "413"? Has he marked through the number "1"? Maybe changed the 3 to a 1? What do these #s mean?