Measure the center to center bolt spacing of your carb. It should be 2 - 11/16.

https://www.thecarburetorshop.com/Carter_YF_Chevrolet.htm

If you have a manual choke YF for a 216, it’s one of only a couple models. Buy your kit from thecarburetorshop.com….as far as I know they are the only ones who will supply the correct needle and seat. And probably the only ones who can assist in identifying your carb if you can’t find a model stamping.

1951 3100