New National Seals Optispark seal for all 95-97 LT1 engines, aka "vented Optispark".  This mounts in the timing cover, and is for the Optispark.   Fits the following:

95-96 LT1/LT4 Corvette
95-97 LT1 Camaro Z28, SS
95-97 LT1 Firebird Formula, Trans Am, Firehawk
Late 94, 95-96 LT1 Impala SS