This is the original 4.2 liter 6 cylinder engine known as the "XK" engine. It has been around in one form or another since 1948! The engine seen here (used in all Series III XJ6's, like my '85) uses Bosch/Lucas L-Jetronic electronic fuel injection. My engine has 126,000 miles on it, which is normal for these cars. The transmission used up through 1987 was a 3 speed Borg Warner unit. Overdrive was not offered until 1988 when they redesigned the entire car.