Please help. I swapped out my 216 for a rebuilt 235 for my 1953 Chevy 3100. I may have mixed up the carbs as the 235 is running so rich that it is fouling and blowing black smoke. I checked the main jets and the one in the carb online is a #57 the one on my bench is a #52....Otherwise the carbs look the same. I assumed tht the 235 would have the larger jet so thought the right one was put in. Not even sure if this is the problem or something else (Also are there other diferences in the 2 carbs forthese engines...? They look the same other than the main jet........Any suggestions would be greatly appreciated!!...Thanks, Sammy