Floats for Holley's 2-bbl and 4-bbl performance carburetors come in center- and side-hung designs.
The floats are made of brass or nitrophyl. Carbs compatible with alcohol need brass floats while carbs with a blow-through, forced induction system require nitrophyl. A draw-through, forced induction system can use either a brass or nitrophyl float.

A notched float is a necessity when using main jet extensions. Such center-hung floats are made of nitrophyl and have notches to clear main jet extensions, allowing the float to operate normally without interference from the extensions.

Except for 510-216-43, all floats are adjustable.