I bought new in '06, still have the original manual & receipt..  spent 2 seasons in my boat before switching it out for 850cfm, been in my garage since.

It's 750 cfm vacuum secondary, model 0-80508S.  $125 obo.. I'm located in Lakewood, CA.

Here's a link to it https://www.holley.com/products/fuel_systems/carburetors/classic_holley/parts/0-80508S