Mako1975,

I seem to recall several recent conversations about Carter YF2100S carbs. You can do a search here: Searching the Site to hopefully help in your dilemma.

I do recall that a recent conversation talked about Carter YF964S models (for 216 applications) which has a smaller throttle body base to match the 216 intake. A picture (attached below) shows that 216 version having a "1-630" throttle base. May be what you got was the correct upper body with the YF2100S stamping, but with a 216 base mated up (others have said this has been a common problem usually caused by indiscriminate re-builders).

Hope you are able to get the issue resolved.

Am sure others with more knowledge and possible helpful solutions will chime in too.

EDIT: Kevin beat me to the answer - lol!
Attachments
YF964S for 216.jpg (110.76 KB, 118 downloads)
1-630 base on YF964S carb

Last edited by Gdads51; 12/03/2022 11:10 PM.

~ Dan
1951 Chevy 3 window 3100
Follow this story in the DITY Gallery
"My Grandpa Carl's Truck and How it Became Mine"
1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver)
US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)