Chevy SBC 350 Polished Ribbed Aluminum Valve Covers - Tall w/Hole They use silicon aluminum bi-metal

They use silicon aluminum bi-metal construction

The Speedmaster LowRise Manifolds are our lowest profile manifold and is also the only one that is street legal on pollution controlled vehicles

Valve stem seals control the lubrication of the valve stem as it slides in the valve guide

best of all

they're guaranteed for life

Chevy SBC 350 Polished Ribbed Aluminum Valve Covers - Tall w/Hole They use silicon aluminum bi-metalDo you want to finish off your engine in style? Try a set of these Speedmaster finned aluminum valve covers. They are manufactured from cast aluminum and have a polished finish. Speedmaster finned aluminum valve covers feature a classic raised, finned design that adds a unique look to your engine. Speedmaster finned aluminum valve covers are the perfect fit for your engine.