there's no 'leaning' needed, the castings numbers say it's a '57 283, the fact that a 60 year old truck obviously had an engine transplant is not at all unusual, particularly when the truck has that many miles on it .... also note that the engine number on the tag doesn't match the one on the engine .... when the engine was changed the original 265 external oil filter was left on, no mystery, and it would be a much better engine for a car hauler than a souped up 235

Bill