Customer brought in an 89' Chevy 1/2 ton truck today. I did a double take when I wrote down the milage. It was 472,xxx.x I asked the fellow if it was the original engine. He said it was, never even replaced the timing chain or valve cover gaskets. Said that he bought the truck new, drove it home and changed the oil that day. It's only seen Pennzoil 10w-30......it did have a Pennz/Fram filter on it too. Changes the oil every 3k. Uses 1qt in 3k. When he wasn't looking I poped the oil filler cap off and could see the casting #'s on the head....No sludge, just a medium brown coating. After I replaced the radiator I ran it to test the T-stat and to burp any air from the system. It started and seemed to run ok, No dead holes or smoke. Guy does time trials on El Mirage lake and uses the truck to tow his racer to the lake and back. Said the original 700R4 trans made it to 305K Which also may be a new record for that trans LOL.