Oil Filler Cap for Chevrolet Performance Valve Covers?


Veteran Member
Oct 9, 2020
710 in raised black?
yup ... it's all a discrete black rubber molding. The rubber oil cap is a molding (likely injection- molding) and the OIL (or 710) is molded into the piece during manufacturing (likely a single-shot); just as most any plastic/rubber molding has a p/n, cavity # etc. Similarly, cast (die-cast) aluminum GM VCs (LT1/L82) have molded-in oil drippers and p/n on their inside and fins/ribs on outside ... all from the mold itself.

In another career, we manufactured gazillions of injection-molded rubber diaphragms for vacuum brake booster shells ... each diaphragm bears a p/n and a cavity # ... all molded-in during a single shot. At a neighboring plant, my colleagues there injection-molded gazillions of Plastic parts; Very similar processes. Who knows ? Even now; you & yours may be relying on those same booster diaphragms?

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