If proper Carter YFs are so difficult to find, would an "improper" Carter YF be preferable to the Rochester B?
I still have the Carter YF that was on Ol' Roy when I got it. I replaced it with a rebuilt Carter YF that is correct for the truck.
The other Carter's markings indicate that it's a Frankencarb made from different Willys parts of the 1950s and 60s. When it was on the truck, it seemed to work ok.
