The Stovebolt Site Forums The Shop Area Engine Shop '57 235 with Rochester B (in a '53) - tuning q's ?

For a "ballpark" idle air screw setting, turn it to the right until it begins to tighten (do this gently) then back it out 1 1/2 turns.
On a cold engine, make sure the choke is working, this should also provide you a higher idle speed because of the idle cam on the choke. Once the engine is warm follow tclederman's procedure above.