They will feature roller-finger followers, electronic throttle control (ETC), forged steel crankshafts, special piston-cooling oil jets, coolant loss protection software, GM’s Oil Life Monitoring System, 32-bit microprocessor, coil-on-plug ignition and iridium spark plugs. First to debut will be a 255-hp 3.6-liter version incorporating variable intake and exhaust valve timing (cam phasing) to optimize starting, idle, low-rpm torque and high-rpm power as well as emissions and economy.