Holley 4779 750 cfm Double Pumper

Mopowers covered my answer.
But what I do when I redo a holley: I have a pane of glass (flat!) that has a half sheet of 80 grit, and half sheet of 320 racer taped to it.
I use it to surface anything that needs to be flat, including accelerator pump housings, and the mating surface on the bowls.