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Engine Numbers

Engine Numbers

by Rob Reilly

Occasionally a question arises about identifying a Jaguar engine, for example
if it has been swapped. The purpose of this list is to identify swapped, used
and orphan engines. Information is still lacking on a few models where
indicated by a ? question mark. Perhaps others will provide the numbers for
those last few, or let the list administrator know if any have been missed or
anything stated incorrectly.

The initial letter or letters of a Jaguar engine serial number generally
indicate what model car the engine was made for.

For sidevalve engines the number may have been taken directly from the series
used by the Standard Motor Co., which supplied these engines. The number is
located on a raised pad in the center of the engine block just below the head
gasket surface on these engines. The SS-90 had head modifications by Harry

Early 2-1/2 Liter pushrod engines also appear to have a Standard number. These
have the Weslake designed OHV head.

The number for the pushrod engines is found stamped on a machined boss on the
right hand side of the block near the rear above the drain petcock; there is
no serial number on the pushrod head. Pre-war engine blocks had the SS hexagon
logo cast into the block on the right hand side; post-war this was changed to
a Jaguar logo.

The number of the XK engine block for earlier models is stamped on the
horizontal shelf above the oil filter, or for later models on the left on the
bell housing flange; on the earlier cylinder heads it is on the vertical face
in front of the front spark plug. If there is no number on an earlier head it
is probably a replacement head obtained through the Jaguar Spares Department.
The practice of numbering heads was discontinued at some point in the late
1960's. Following the initial letter(s) there are generally four numbers
followed by /7 or /8 or /9, which indicates the compression ratio.

The number of the V-12 engine block is stamped in the Vee between the heads at
the rear. There is no serial number on the heads.

For the AJ-6 engines the engine serial number is on the right hand side of the
block next to the distributor.

For V-8 engines the engine number is located where?

In the following list the format is the initial letters followed by xxxx
indicating three or four or five numerals for the sequential numbering, or
alternatively 0001> indicating engines were numbered sequentially from this

Engine/Head Numbers

Sidevalve Engines

? 747 cc Austin Swallow 4 cyl.
? 1548 cc Morris Cowley Swallow
? 990 cc Fiat Swallow 4 cyl.
? 1190 cc Swift Swallow
? 1271 cc Wolseley Hornet Swallow (OHC 6 cyl., not sidevalve)
? 1287 cc Standard Swallow 4 cyl.
? 2054 cc Standard Swallow 6 cyl.
13xxxx 2054 cc, 2143 cc (16 hp) SS-I 6 cyl.
247xxx 2552 cc, 2663 cc (20 hp) SS-I 6 cyl.
15xxxx 1052 cc (9 hp), 1343 cc (10 hp), 1608 cc (12 hp) SS-II 4 cyl.
248xxx 2663 cc SS-90 6 cyl.
249xxx 2663 cc SS-90 6 cyl.
55xxx 1-1/2 Liter SS Jaguar saloon & DHC 4 cyl.
58xxx 1-1/2 Liter SS Jaguar saloon & DHC 4 cyl.
59xxxSS 1-1/2 Liter SS Jaguar saloon & DHC 4 cyl.
60xxx 1-1/2 Liter SS Jaguar saloon & DHC 4 cyl.

OHV Pushrod Engines

249xxx 2-1/2 Liter SS-100, SS-Jaguar saloon & DHC
250xxx 2-1/2 Liter SS-100, SS-Jaguar saloon & DHC
251xxx 2-1/2 Liter SS-100, SS-Jaguar saloon & DHC
252xxx 2-1/2 Liter SS-100, SS-Jaguar saloon & DHC
253xxx 2-1/2 Liter SS-100, SS-Jaguar saloon & DHC
LxxxxE 2-1/2 Liter SS-100, SS-Jaguar saloon & DHC
MxxxxE 3-1/2 Liter SS-100, SS-Jaguar saloon & DHC
KxxxxE 1-1/2 Liter SS Jaguar saloon & DHC 4 cyl. 1938-40
KBxxxxE 1-1/2 Liter "Mark IV" 4 cyl. 1945-48
Pxxxx 2-1/2 Liter "Mark IV" 1945-48
Sxxxx 3-1/2 Liter "Mark IV" RHD 1945-48
SLxxxx 3-1/2 Liter "Mark IV" LHD 1945-48
Hxxxx 2.5 Liter Mark V
Txxxx 3.5 Liter Mark V early
Zxxxx 3.5 Liter Mark V late

DOHC XK Engines

Wxxxx XK-120 early
Fxxxx XK-120 late
Axxxx Mark VII
Bxxxx Mark VII
Dxxxx Mark VII
Exxxx C-type, D-type
Gxxxx XK-140
Nxxxx Mark VII & Mark VIII
NAxxxx Mark VIII
NCxxxx Mark IX
NExxxx Mark IX
Vxxxx XK-150 3.4 Liter
VSxxxx XK-150S 3.4 Liter
VAxxxx XK-150 3.8 Liter
VASxxxx XK-150S 3.8 Liter
BBxxxx 2.4 Liter Mark 1
BCxxxx 2.4 Liter Mark 1
BDxxxx 2.4 Liter Mark 1
BExxxx 2.4 Liter Mark 1
BGxxxx 2.4 Liter Mark 2
BHxxxx 2.4 Liter Mark 2
BJxxxx 2.4 Liter Mark 2
KCxxxx 3.4 Liter Mark 1
KExxxx 3.4 Liter Mark 1
KFxxxx 3.4 Liter Mark 1
KGxxxx 3.4 Liter Mark 2
KHxxxx 3.4 Liter Mark 2
KJxxxx 3.4 Liter Mark 2
LAxxxx 3.8 Liter Mark 2
LBxxxx 3.8 Liter Mark 2
LCxxxx 3.8 Liter Mark 2
LDxxxx 3.8 Liter Mark 2
LExxxx 3.8 Liter Mark 2
Rxxxx 3.8 Liter E-type
RAxxxx 3.8 LIter E-type
EC1001 Lightweight E-type
RA1343-57 (excl 1352) wide angle head Lightweight E-type
ZAxxxx 3.8 Liter Mark 10
ZBxxxx 3.8 Liter Mark 10
ZDxxxx 4.2 Liter Mark 10, 420 G
7A30001 4.2 Liter Daimler Sovereign (420 equiv.)
7B1001 3.4 Liter S-type
7B50001 3.8 Liter S-type
7D50001 4.2 Liter Mark 10, 420 G
7Jxxxx 340, 240 saloons
7Exxxx 4.2 Liter E-type Series 1 and 1.5
7Fxxxx 420
7Lxxxx 2.8 Liter XJ6
7Lxxxx 4.2 Liter XJ6
7Mxxxx DS420 Limousine
7Rxxxx 4.2 Liter E-type Series 2
8LxxxxxS 4.2 Liter XJ6

SOHC V-12 Engines

7Sxxxxx 5.3 Liter E-type
7P1001 5.3 Liter XJ12/Daimler Double SIx Series 1 w/carburetters
7P4000 5.3 Liter XJ12 & D6 Series 2 w/carburetters
7P25001 5.3 Liter XJ12 & D6 Series 2 w/fuel injection
7P42300 5.3 Liter XJ12 Series 3 Pre-HE (suffix ? = 9:1, suffix HA = 10:1)
7P45001 5.3 Liter XJ12 Series 3 HE
8S1001 5.3 Liter XJS non-H.E.
8S18001 5.3 Liter XJS H.E.
? 6.0 Liter
Note that for V12s 1971 through 1979, LA and LB suffix was 7.8:1 CR and SA and SB suffix was 9:1 CR. For 1980, suffix HA was 10:1 CR. From 1981 ?? suffix was 11.5:1 CR and ?? suffix was 12.5:1 CR.

AJ-6 Engines

? 3.6 Liter XJS
? 4.0 Liter XJS
? 2.9 Liter XJ40 style XJ6
? 3.2 Liter XJ40 style XJ6
? 3.6 Liter XJ40 style XJ6
? 4.0 Liter XJ40 style XJ6

AJ-? 6 Cylinder Engine

? 3.2 Liter X300 style XJ6
? 4.0 Liter X300 style XJ6

V-8 Engines

CCxxxxxxxxxx XK8
? XJ8
? XJR8

If you have any questions or comments send e-mail to:
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