MACE PERFORMANCE LOWER MANIFOLD INSULATOR TO SUIT HOLDEN CALAIS VL RB30E RB30ET 3.0L I6Exclusive to Mace Engineering, here we have our design registered lower manifold insulators to suit the Holden VL Commodore fitted with an RB30 3. 0L 6 cylinder engine. Compatible with both turbo and non turbo engines. 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