Well stick a fork in me I'm done...new info. as follows on one carb the number 938S with the letter C in a circle...cast iron section the number 1-630 and 2-11/16 between bolt holes and 1.5"hole...the other carb looks exactly the same but for Carter YF and the C & R both of which are in circles and no "s" numbers stamped on the carb.? Steve