Editing Jaguar XK engine (section)

===3.4-litre===

The first production use of the XK [[straight-6]] was in the 1948 [[Jaguar XK120]], which used the {{cvt|3441|cc|L cuin|1}} version with a [[Bore (engine)|bore]] x [[Stroke (engine)|stroke]] of {{convert|83x106|mm|2|abbr=on}}. It had an iron block without cylinder liners and aluminium [[cylinder head]]. It had a wider gap between cylinders 3 and 4 than between the other cylinders. The 3.4 was first rated at {{convert|160|bhp|PS kW|0|abbr=on}} [[Horsepower#SAE gross power|SAE gross]] at a [[compression ratio]] of 8:1, rising to {{convert|210|bhp|PS kW|0|abbr=on}} SAE gross with the C-type cylinder head (confusingly not the head from the C-Type as raced at Le Mans) all the way to {{convert|250|bhp|PS kW|0|abbr=on}} SAE gross with the "straight port" head at a compression ratio of 9:1 as fitted to the XK150SE.

Almost as soon as the new compact Jaguar [[Jaguar Mark 1|2.4-litre]] was released, there was pressure on Jaguar to fit the 3.4-litre engine to it. This was duly done in February 1957, the car being known as the Jaguar 3.4-litre. The designation "Mark 1" for these cars was applied retrospectively, after the release of the Mark 2 in 1959.

The original 3.4-litre XK was used in the following road cars:
* [[Jaguar XK120]] - 1948-53, "Standard (or "A type")" cylinder head, bare aluminium finish, 2 × [[SU Carburettor|SU H6 carburettors]]. The XK 120 C came with the C-type head (red) as an option from 1951 to 1952 with 2 × SU H8 carburettors. In 1953, the XK 120 C switched to a triple 40 DCOE [[Weber carburetor]] setup. The XK 120 SE and M came with the C-type head as an option with 2 × SU H6 carburettors (occasionally SU H8)
* [[Jaguar XK140]] - 1954-57, "Standard (or "A type")" cylinder head, 2 × SU H6 carburettors. The XK 140 SE or M came with the C-type head as an option, painted red with 2 × SU H6 or H8 carburettors
* [[Jaguar XK150|Jaguar XK 150 3.4]] - 1957-61, "B type" cylinder head, painted light blue-green, 2 × SU HD6 carburettors
* [[Jaguar XK150|Jaguar XK 150 3.4S]] - 1957-61, "Straight port" cylinder head, painted orange, 3 × SU HD8 carburettors
* [[Jaguar Mark VII]] - 1950-54, "A type" then "C type" (as option from April 1953) cylinder head, unpainted aluminium, 2 × SU H6 carburettors
* [[Jaguar Mark VII|Jaguar MkVIIM]] - 1954-57, "C type" cylinder head, 2 × SU H6 carburettors, some had high-lift cams
* [[Jaguar Mark VIII]] - 1956–1958, "B type" cylinder head, painted light blue-green, 2 × SU HD6 carburettors
* [[Jaguar Mark 1|Jaguar 3.4-litre 'Mark 1']] -<ref>''Jaguar Workshop Manual 2.4- and 3.4-litre Mks. I and II, 3.8-litre Mk. II with automatic transmission 1956 to 1961'', Scientific Publications, Australia</ref> 1957-59, "B type" cylinder head, painted light blue-green, 2 × SU HD6 carburettors
* [[Jaguar Mark 2|Jaguar 3.4-litre Mark 2]] - 1959-67, "B type" cylinder head, painted light blue-green, 2 × SU HD6 carburettors
* [[Jaguar Mark 2|Jaguar 340 Mark 2]] -<ref>''Jaguar Mk II Workshop Manual No.186'', InterEurope Ltd, {{ISBN|0-85666-020-5}}</ref> 1967-68, "B type" cylinder head, ribbed cam covers, 2 × SU HD6 carburettors
* [[Jaguar S-Type (1963)|Jaguar S-Type 3.4]] - 1963-68, "B type" cylinder head painted light blue-green, smooth cam covers, 2 × SU HD6 carburettors