Used crankshaft pulley bolt retainer plate. This metal plate sits under the bolt heads as a reinforcement. For 4-bolt Pontiac pulleys only. 4 3/4" OD x 2 3/8" ID. Fits the following:
70-79 Firebird/Trans Am with 350/400/455 (Pontiac engine only)
The item in the photo is the exact item being sold.