Are there any opinions on the rebuilt carter yfs from classic Chevy trucks?
We can't give you any encouragement on these because we don't have any idea who rebuilt them, and much worse than that nobody other than the person who worked on them has any earthly idea what parts might be inside them. No idea whatsoever. Unfortunately anybody doing this sort of work can swap parts from any YF into any other YF. The most common problem I've seen is that the float bowl (which carries the identifying marking of the YF model) can be swapped with throttle bodies and air horns of any model YF handy. This creates a mongrel carburetor which will never ever work as it was designed. For this reason alone, I would not buy one of them. Trust me, your money can be spent better elsewhere. Would you like examples? Here are two:https://tinyurl.com/y5678u2vhttps://tinyurl.com/y3fembwo
On both of these, the seller thinks this is a 3211s. It is no more a 3211s than it is a spaceship. No 3211s was ever made with a manual choke. These are guaranteed to be "frankencarburetors" assembled from (a) one 3211s float bowl and (b) throttle bodies and air horns from some other manual choke Carter body. They won't work.
Or this one:https://tinyurl.com/y2hnwvhv
It claims to be NOS and it may be, but the images are out of focus and it appears to be rusted to the point it will never be ok again.
Over the past couple of years I've gone to great lengths to find as much of the remaining Carter YF information as possible so that any carburetor I have or that I sell can be checked and guaranteed to be what it should be...and it takes a while and some careful study to do this. It most definitely is not the sort of work a wholesale rebuilding operation is ever going to do. They can't afford to do work like that because time is money and their employees are paid based on the number of carburetors they "rebuild" during their shift.
Given your setup I would say you'd do best with a Carter 3211s carburetor although other Carter types might work fine. Are you interested in manual choke or auto choke?