BBBs were designed with the valve covers upside down IMHO. Shoulda gone with the Olds or Caddy style. ws
They worked great for me. The spacers provide a much wider base for the gasket to contact. I glued the spacer to the head with Ultra Black RTV. Used rubber gaskets, and glued them to the stock cover. A light coat of Gasgacinch along the exhaust side of the gasket, and the Almack clamps. Took the car on a 100 mile cruise today, didn't leak at all, never even got a wiff of burned oil. At least I know I can remove and reinstall the covers if I need to.
