This is a Front Holley Carb.
Holley 4 Barrel Carb #821030A16 changes to #821030T16 for $733.75
The Carb Repair Kit is #42270A1 for $22.85 (gaskets only).
The Carb Base Gasket (spacer) is #818892 for $29.95
Floats, Needles & Seats and Accel. Kits are NSS.