sources may describe as "silver", and had ribbed cam covers. The 2.8-litre XK6 was used in the following cars: XJ6 2.8 Series 1 - 1968-73, 2 × SU HD8 carburettors Daimler Sovereign 2.8 'XJ6' Series 1 – 1969-72, 2 × SU HD8 carburettors XJ6 2.8 Series 2 - 1973-74, 2 × SU HS8 carburettors "New" 3.4-litre Introduced in 1975 to replace the 2.8 in the entry level XJ6, the new 3.4 was not a simple revival of the original XK. Whilst it shared the old 3.4’s bore and stroke of and respectively, it carried over some features of the newer 4.2 litre engine - the main bearing spacings and bearing sizes, and stiffer bottom end but dispensing with the cylinder liners used by the 3.8 and 4.2. However the cylinder spacing remained as the original 1948 design. With 83mm bore, the cylinders needed to line up with the combustion chambers in the cylinder head (whose centres remained as the original 1948 design right up to the end of XK-engine production. It used a straight port head and delivered DIN net and far superior torque to the 2.8. The "new 3.4" used the straight port head, had ribbed cam covers and the heads were unpainted. The "New 3.4" litre XK6 was used in the following cars: XJ6 3.4 Series 2 - 1975-79, ribbed cam covers, 2 × SU HS8 carburettors. From 1977, 2 × SU HIIF7 carburettors Daimler Sovereign 'XJ6' 3.4 Series 2 – 1975-79, ribbed cam covers, 2 × SU HS8 carburettors. From 1977, 2 × SU HIIF7 carburettors XJ6 Series 3 - 1979-86, ribbed cam covers, 2 × SU carburettors Cylinder head types The following table relates XK cylinder head type to Jaguar/Daimler model and includes the paint colours applied to certain versions of the cylinder head in the 1950s and 60s. Unpainted heads are sometimes referred to as "silver" but this is merely the natural colour of the aluminium alloy. See also Jaguar AJ-V6 engine Jaguar V12 engine References External links Four cylinder XK engine page at the Jaguar Daimler Heritage Trust Six cylinder XK engine page at the Jaguar Daimler Heritage Trust Military version of the six cylinder XK engine page at the Jaguar Daimler Heritage Trust "The XK Engine" an article by Roger Bywater of AJ6 Engineering for Jaguar World magazine XK Performance XK6 Gasoline engines by model Straight-six engines