MACE 1.98 ULTRA HIGH RATIO ROLLER ROCKER KIT TO SUIT HOLDEN ECOTEC L36 L67 SUPERCHARGED 3.8L V6Exclusive to Mace are our 1. 98: 1 ultra high ratio roller rockers (up from 1. 65: 1) to suit VS VX Commodores and similar platforms fitted with the Ecotec 3. 8L and the L67 Supercharged 3. 8L V6 engines. These are the highest commercially available rockers on the market for the Ecotec and L67 engines. It's a very cost effective way to increase the performance of a Commodore, by increasing valve lift, allowing your engine to breathe much more