Ultralite Roller Rocker Set 1.8 Ratio (8mm Mount, Shaft Bolt-On Adjustable) YT66Ultralite Roller Rocker Set 1. 8 Ratio (8mm Mount, Shaft Bolt On Adjustable)Suit GM LS Series LS3 L92 L98 6. 2L YT6668 6668 Yella Terra Ultralite Yella Terra has developed shaft and pedestal systems for late model engines that have less than half the nose weight of other rocker designs to correct valve float when some performance camshafts are used with lightweight valve train components and conical springs. The result is greater RPM potential without