[CWizard]

Hyde - The carb is a 750 cfm Holley 4150 Street HP, supporting a 520 hp stroked Windsor. Vacuum lines all plugged. I haven't tried going down on the primary nozzles because I see no puffs of black smoke that would indicate an overly rich mixture when I punch it, not even with the relatively large .040 nozzles. But you raise a good point - I'll try going down and see what happens.
Thanks.