I bought a 59 Olds for the motor for my 53 Olds and when I got it running it would only run on 4 cylinders,someone before me soldered up one side of the carb which I think was to try to get better gas mileage. That drove me nuts trying to figure it out and at the same time had a 55 Olds doing the same but it was a chunk of dirt in one jet.