MACE 12MM UPPER MANIFOLD INSULATOR KIT TO SUIT HOLDEN CALAIS VL RB30ET TURBO 3.0L I6Exclusive to Mace Engineering, here we have our design registered upper manifold insulator to suit Holden Commodores and similar platforms fitted with the RB30ET Turbo I6 engine. What are manifold insulators and what do they do? Manifold insulators are a thermal insulating spacer that mount between your engine block and intake manifold. Made from a heat blocking composite, our manifold insulators will increase power from your engine by keeping the