Holley 3310-2 2946 4bbl

As I am not a carb guy I did a quick search through the net and find the 3310 is pretty dang universal hot rod carb. I see it can have 1 or 2 metering blocks. The carb I have for sale is what I believe to be the 750cfm carb. The numbers I posted are stamped right on the main body.
If anyone has more input it might be helpful.

-RPM