tell you what, call around and get quotes on rebuilding this carburetor by qualified people.
then price a strip kit which is the tuning kit made by carter that is out of production that you need to tune it to your specific application where ever you are racing. this is a racing carburetor.
then compare it to the cost of other racing carburetors on the market today with easy to get parts to tune it.
consider that fuel injection is quickly becoming the choice over carburetors.
what you have is a dirty turd that was once the most advanced racing carburetor on the planet, be it that it was expensive and time consuming to tune, that may never run again because it true condition is unknown. it just may be that the phenolic resin fuel body is warped or cracked beyond repair. do the mixture screws actually turn in and out? dont force them, they will bust off. and if anything is missing, where will you get those parts from?
how much would pay knowing all this?
if this carb was in the box new old stock or was rebuilt in working order with a guarantee, then you might have something of value.