1968 340 AVS 4425S carb problems

Well, just to add to the confusion- I now have three 1968 AFB's. All are stamped with the correct factory number but one of them has the standard idle screws. I was there in 1968 and have never seen one like this one. Obviously there was some variation at the factory. A 1969 carb will be a little bit different as it will have provision for a vapor recovery system to return vapors back to the gas tank. So it really depends on you- how correct do you want to be?