If you have the engine tag still attached to the engine - just in front/below the thermostat housing - or perhaps the original engine number in the log book then the following should help you determine which engine you have. 

Original engine identification numbers 

850cc 
8A Austin up to 25000 
8MB Morris up to 25000 
8AM Austin & Morris 25000 onwards 
8AH Austin & Morris Automatic 
8AJ Austin & Morris closed circuit breathing 
8AK Austin & Morris automatic with closed circuit breathing 
8WR Wolseley Hornet & Riley Elf 
8AC Moke 
85H/101 All variants 1969 onwards 

Note: third suffix letter denotes compression type, L = Low, H = High, e.g. 8AM/U/H101 denotes high compression. 

998cc 
9WR Wolseley Hornet & Riley Elf Mk2, pre closed circuit breathing 
9AD Austin, Wolseley Hornet & Riley Elf Mk2 with remote type gearbox and closed 
circuit breathing 
9AE Wolseley Hornet & Riley Elf Mk3 
99H/-/101 on Wolseley, Riley, Mini 1000, Clubman1000 1970 onwards and Mk3 with dished 
piston 
99H/791 Mini 1974 onwards with dished piston 
99H/997 1980 onwards A+ block, flat top psitons, economy fitment with 2.95 final drive 
99H/A97P A+ block with dished pistons, pre-A+ gears, 3.44 final drive & 12-inch wheels 

998 A+ block with centre locating tang in main cap, 1985 onwards 
Flat top piston with circlip wrist pin retention 
99H/B81 Up to engine number 127431 
99H/C20 Up to engine number 105023 
99H/997 From engine number 127422 with 2.95 final drive 
99H/A35P 

Flat top piston with press fit wrist pin 
99H/B81 From engine number 127432 
99H/C20 From engine number 105024 
99H/D80 

Flat top pistons with press fit wrist pins, Lead-free cylinder head 
99H/G30 or G32 or G33 
99H/F15 or F16 
99H/E20 or E21 
99H/D81 
LBB10089 

Dished pistons with circlip wrist pin retention 
99H/B83P Up to engine number 102908 
99H/B84P Up to engine number 100216 

Dished pistons with press fit wrist pin 
99H/B83P From engine number 102909 
99H/B84P From engine number 100217 

Dished pistons with press fit wrist pin, Lead-free 
99H/G31 
99H/E22 
LBB10175 

1100cc (1098cc) 
10AMW/Ta Clubman Estate and Austin 110 (ADO16 shape) 
10H791 Clubman saloon 
10H/-/H All Austin 1100 2 & 4 door derivative Saloons (ADO16 shape) 
10GR/Ta/H MG1100 (ADO16 shape) 
10GRB/Ta/H MG1100 & Wolseley 1100 (ADO16) 
10V/Ta/H Vanden Plas 1100 (ADO16 shape) 

997 Cooper 
9F/Sa/H101 to 2637 except 19201 to 20410 (became 1070S) 

998 Cooper January 1964 onwards) 
9FA/Sa/H Mk1 Austin pre closed circuit breathing 
9FD/Sa/H Mk1 Morris up to engine number 1934, all Austin Mk2 closed circuit breathing and 
Morris Mk2 from engine number 1935-33660 with closed circuit breathing 
9FD/Xe/H 4 syncro gearbox introduced 
99/-/H Last of manufacture 1969 

Cooper S variants 
970cc 
9F/Sa/X Engine numbers 29001-29003 with Tecalamit filter 
9FD/Sa/X Closed circuit breathing introduced with Tecalamit filter 
9FE/Sa/X Closed circuit breathing, oil filter with oil light switch introduced 
9F/Sa/X Engine numbers 29039-30029 Purolator oil filter with oil light switch and closed 
circuit breathing 
1070cc 
9F/Sa/H Engine numbers 26501 to 33660 and 19201 to 20410 
9FD/Sa/H Engine numbers 33661 to 33948 with closed circuit breathing and oil light switch in 
oil filter head 
1275cc 
9F/Sa/Y Engine numbers 31001 to 31504 pre closed circuit breathing with Purolator oil filter 
9FD/Sa/Y Closed circuit breathing with oil light switch on filter housing after engine number 
32178 
9FE/Sa/Y Closed circuit breathing with oil light switch on Purolator filter housing and piston 
design change 
9F/Sa/Y From engine number 32378 onwards, cosed circuit breathing with Purolator filter 
with oil light switch, Aeg510 camshaft introduced at engine number 40006, cross- 
drilled EN40Bcrank at engine number 42730 and metal dipstick tube at engine 
number 42548 onwards 
12H397 Cooper S Mk3 with dynamo, negative earth and Tuiftrided EN16T crankshaft 
12H398 Cooper S Mk3 with alternator, negative earth and Tuftrided EN16T crankshaft 

Note: Only Cooper S engines with prefix '9F' had EN40B forged steel, nitrided crankshafts. All other A-series engines had EN16T steel crankshafts which were only Tuftrided on Mk3 'S' and Austin 1300GT (ADO16) and were stamped 12G1683. 

1275cc, Solid wall block (no tappet chest covers) 
12G/Ta/H ADO17 shape Wolseley, Riley, MG & Vanden Plas fitted with S rods 
12H379 1275GT with dynamo, negative earth, electric fuel pump and remote type 
gearbox 
12H380 1275GT with alternator, negative earth, electric fuel pump and remote type 
gearbox 

12H389 1275GT with dynamo, negative earth, mechanical fuel pump and remote type 
gearbox 
12H390 1275GT with alternator, negative earth, mechanical fuel pump and remote type 
gearbox 
12H706 1275GT with alternator, negative earth, mechanical fuel pump and rod change 
gearbox 
12H397 Cooper S Mk3 with dynamo and negative earth 
12H398 Cooper S Mk3 with alternator and negative earth 
12H/-/ 1275 Austin ADO16 & Allegro 
12H610/635 Innocenti Mini with duplex cam drive gears and 11-stud head 
12H719/832 Innocenti Mini with simplex cam drive gears and 11-stud head 

1275cc, 1990 onwards (12A numbers) 
12A/2A Carburrettor type 
12A/2B Carburrettor and catalyst type 
12A/2D SPi (Single Point injection - Tbi, throttle body injection) with 9.4-1 CR 
12A/E SPi (Tbi - throttle body injection) with 10-1 CR 
With the following suffixes: 
F53 10.0-1CR, 3.105 final drive, catalyst, oil cooler 
F75 9.4-1CR, SPi, 3.105 final drive, closed loop catalyst 
F76 9.4-1CR, automatic with closed loop catalyst 
F77 10.0-1CR, SPi Cooper, 3.2 final drive, closed loop catalyst 
G01 10.0-1CR, 3.105 final drive, catalyst, no oil cooler 
G03 9.4-1CR, 3.105 final drive, catalyst, May 1992 onwards 
G04 9.4CR, 2.76 final drive, catalyst, French only spec 
G05 9.4-1CR, automatic with catalyst 

Factory replacement engine reference numbers (i.e. New, and Gold and Silver Seal units) 
8G28 850cc - Oil feed to primary gear type crank with 1.375-inch tail shaft 
8G35 850cc - Deva bush conversion type crankshaft with 1.375-inch tail shaft 
8G45 850cc - Gold Seal, 1.5-inch self oiling primary gear/crankshaft type 
GSE1101E 850cc - Gold Seal unit 
RKM1101E 850cc - Silver Seal unit 
BHM1307E 850cc - Gold Seal unit, 85H prefix replacement 
8G18 997cc Cooper - Oil feed to primary gear type crankshaft 
8G29 997cc Cooper - Deva bush type primary gear and crankshaft 
8G36 997cc Cooper - Oil feed converted primary gear and crankshaft 
8G33 998cc Cooper - Fitted with 28G193 (12G202) cylinder head 
8G40 998cc Cooper - 28G222 (12G295)cylinder head introduced 
8G42 998cc Cooper - Closed circuit breathing rocker cover and side plates 
8G49 998cc Cooper - Purolator oil filter with oil light switch introduced 
GSE1103E 998cc Cooper - Gold Seal unit, was RKM1120E Silver Seal 
RKM1103E 998cc Cooper - Silver Seal unit 
8G57 998cc - New from 1969 and exchange for all pre-A+ up to 1981 
GSE1102E 998cc -Gold Seal unit, was RKM1119E Silver Seal unit, pre-A+ up to 1981 
RKM1102E 998cc - Silver Seal unit, pre-A+ up to 1981 
RKM1119E 998cc - Silver Seal unit, replaced by RKM1102E, pre-A+ up to 1981 
BHM1232 998cc - Low compression dished piston, CAM6267 camshaft, early cylinder head 
and crankshaft main bearings with side locator tang, A+ 
BHM1377 998cc - High compression flat top piston, CAM4717 camshaft, early cylinder head 
and crankshaft main bearings with side locator tang, A+ 
BHM1458 998cc - Low compression piston, CAM6267 camshaft, late A+ cylinder head and 
crankshaft main bearings with central locator tang, A+ 
BHM1460 998cc - High compression press-fit wrist pin piston, CAM4717 camshaft, late A+ 
cylinder head and crankshaft main bearings with central locator tang, A+ 
LBB10089 998cc - Low compression press-fit wrist pin piston, CAM6267 camshaft, lead - 
free late A+ cylinder head and crankshaft main bearings with central 
locator tang, A+ 
8G156E 1100cc - Clubman, Special and Austin 1100 (ADO16) 
RKM1150E 1100cc - Silver Seal unit for Clubman and Special 
RKM1151E 1100cc - Silver Seal unit for Clubman and Special 
BHM1042 1100cc - New and Gold Seal units for Clubman and Special, 1974-1980 
BHM1229 1100cc - New and Gold Seal units for Clubman and Special, A+ Block, 1980 on 
8G38 970cc - Gold Seal unit, pre closed circuit breathing, Cooper S 
8G41 970cc - Gold Seal unit with closed circuit breathing sideplates, Cooper S 
8G46 970cc - Gold Seal unit withoil light switch in filter housing, Cooper S 
8G133 1070cc - Gold Seal unit, pre closed circuit breathing, Cooper S 
8G153 1070cc - Gold Seal unit with closed circuit breathing side plates, Cooper S 
8G145 1275cc - Pre closed circuit breathing unit, Cooper S 
8G154 1275cc - Closed circuit breathing side plates unit, Cooper S 
8G155 1275cc - Oil filter housing with oil pressure light switch, Cooper S 
8G174 1275cc - Fitted with AEG510 camshaft, Cooper S 
38G464 1275cc - Introduced in 1970, most of which were fitted with EN16 Tuftrided 
crankshaft 
8G200 1275cc - New and Gold Seal units Clubman 1275GT 
38G527 1275cc - New and Gold Seal units for engine numbers prefixed 12H706, 12H707 & 
12H831 for Clubman 1275GT 
RKM1130E 1275cc - Silver seal unit, was RKM1112E, for Clubman 1275GT, pre-A+ 
RKM1152E 1275cc - Silver Seal unit for Clubman 1275GT, pre-A+ 
RKM1112E 1275cc - Silver Seal unit for Clubman 1275GT, pre-A+ 
BHM1220 1275cc - A+ unit for Clubman 1275GT 
8G199E 1275cc - Gold Seal unit with Duplex cam drive gears for 1300GT (ADO16) and 
Innocenti 1300, 11-stud cylinder head 
38G559E 1275cc - Gold Seal unit with Simplex cam drive gears for engine numbers prefixed 
12H719 and 12H832, for 1300GT (ADO16) and Innocenti 1300, 11-stud 
cylinder head 
GSE1109E 1275cc - Gold Seal unit for 1300GT (ADO16) and Innocenti 1300, 11-stud cylinder 
head 
RKM1133E 1275cc - Silver Seal unit for 1300GT (ADO16) and Innocenti 1300, 11-stud 
cylinder head 
BHM1209E 1275cc - Gold Seal unit, replaced all Innocenti 1300 engines from engine numbers 
prefixed 12H610, 12H635 and 12H832 

Notes: 
All engines pre-fixed with 'GSE' or 'RKM' were of UNIPART origin when BL split its parts organisation. 

'E' at the end of a part number denotes it is a reconditioned, service unit only (basic engine assembly with no ancillaries). 

'N' at the end of a part number denotes a brand new unit.