This is a 4.0ltr Nikasil engine has been stroked to a 4.2, larger bottom pulley, smaller top pulley and a sleeved idler to take up the belt slack, port and polished heads, aluminium coil pack covers. Larger independant supercharger cooling system, filled with glycol with uprated pump, 3" thick radiator with the gearbox cooling system removed and run through a seperate oil cooler, uprated fan assembly