Mercruiser Engines Block ID Codes – Small Block V8 Marine Engines

The specific model/vintage of Mercruiser Marine Engines can be determined by looking at the last letters of the engine code which is stamped in all complete Marine Longblocks by General Motors at the time of assembly. If the serial number and/or model decals are missing, the Marine Engine code will help to determine the engine model. Refer to the drawing below for the specific engine code location on your Mercruiser Engine.

Information you need from the engine code, example M01187MH. 7=General Motor's model year in this case 1997, BUT this could also be 1987 or 1977. MH = Type of engine. The 350 cid V8 Mercruiser models 5.7L, 350 Mag Mpi, Black Scorpion Ski, etc.

GM V8 305 cid (5.0L) - Sterndrive Models (LH rotation), flat lifters

Model GM Code Comments Flywheel Diameter in. (mm)
898 MN 1977–1980, 1982–1984 12–3/4 (324)
898 MX 1981 12–3/4 (324)
228 MJ 1977–1980, 1982–1984 12–3/4 (324)
230 PD 1228 MY 1981 12–3/4 (324)
200 MN 1985 12–3/4 (324)
200 MY 1985, start 14 in. flywheel 14 (356)
200 PY 1986, start full circle rear seal 14 (356)
200 PC 1987, start new cylinder heads 14 (356)
230 MJ 1985 12–3/4 (324)
230 MZ 1985, start 14 in. flywheel 14 (356)
230 PZ 1986, start full circle rear seal 14 (356)
987 PD 1987, start new cylinder heads 14 (356)
5.0L PC 1988–1990 14 (356)
5.0L ZC 1990–1995 14 (356)
5.0LX PD 1988–1990 14 (356)
5.0LX ZD 1990–1995 14 (356)

 

GM V8 305 cid (5.0L) - Inboard Models (rotations shown), flat lifters

Model GM Code Comments Flywheel Diameter in. (mm)
198 MR (MS) 1977, LH (RH) 14 (356)
228 MA (MB) 1977–1980, LH (RH) 14 (356)
230 MA (MB) 1981–1985, LH (RH) 14 (356)
230 PA (PB) 1986, LH (RH), start full circle rear seal 14 (356)
230 PF (PH) 1987, LH (RH), start new cylinder heads 14 (356)
5.0L PF (PH) 1988, LH (RH) 14 (356)

 

GM V8 305 cid (5.0L) Gen+ - Sterndrive Models (LH rotation), roller lifters

Model GM Code Comments Flywheel Diameter in. (mm)
5.0L ZA 1998–2001, start Gen+, start MerCruiser 2–bbl intake,0ZA, start Toluca production 14 (356)
5.0L ZB 2002–UP, 2ZB, MerCruiser 2–bbl intake 14 (356)
5.0L EFI ZA 1998–2001, start Gen+, start MerCruiser 2–bbl intake,0ZA, start Toluca production 14 (356)
5.0L MPI ZB 2002–UP, 2ZB, start GM IAFM (GMEFI) 14 (356)

 

GM V8 350 cid (5.7L) with Flat Lifters - Sterndrive Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
255 WH 1974–1976 12–3/4 (324)
250 WT 1977 12–3/4 (324)
260 WT 1978–1980, 1982–1985 12–3/4 (324)
260 WS 1981 12–3/4 (324)
260 WB 1985, start 14 in. flywheel 14 (356)
260 AB 1986–1987, start full circle rear seal, 7AB, start newcylinder heads 14 (356)
350 Mag AB 1986, start full circle rear seal 14 (356)
350 Mag AS 1987–1990, start new cylinder heads, GM hi–rise intake 14 (356)
350 Mag MS 1990–1991, start GM hi–rise intake 14 (356)
5.7L AB 1988–1990 14 (356)
5.7L MB 1990–1995 14 (356)
5.7L MJ 1996–1997, GM 2–bbl intake 14 (356)
5.7L Bravo AS 1989–1990, start new cylinder heads, GM hi–rise intake 14 (356)
5.7L Bravo MS 1990–1991, start GM hi–rise intake 14 (356)

 

GM V8 350 cid (5.7L) with Flat Lifters - Ski Models (rotations shown)

Model GM Code Comments Flywheel Diameter in (mm)
5.7L WB (WR) 1985, LH (RH) 14 (356)
5.7L AB (AR) 1986–1990, LH (RH), start full circle rear seal, 7AB (AR), startnew cylinder heads 14 (356)
5.7L MB (MR) 1990–1993, LH (RH) 14 (356)
5.7L MB (NR) 1993–1995, LH (RH) 14 (356)
5.7L MJ 1996–1997, LH, start GM 2–bbl intake 14 (356)

 

GM V8 350 cid (5.7L) with Flat Lifters - Inboard Models (rotations shown)

Model GM Code Comments Flywheel Diameter in. (mm)
255 WH (WJ) 1975, LH (RH) 14 (356)
255 WN (WR) 1976–1980, LH (RH) 14 (356)
260 WN (WR) 1981–1985, LH (RH) 14 (356)
260 AN (AR) 1986–1987, LH (RH), start full circle rear seal, 7AN (AR), LH(RH), start new cylinder heads 14 (356)
5.7L AN (AR) 1988–1990, LH (RH) 14 (356)
5.7L MN (MR) 1991–1993, LH (RH) 14 (356)
5.7L NN (NR) 1993–1995, LH (RH) 14 (356)

 

Mercury Racing built Sterndrive Models (LH rotation), 4 bolt mains

Model GM Code Comments Flywheel Diameter in. (mm)
280 WK 1975–1976, GM hi–rise intake 12–3/4 (324)
300 Tempest WK 1984–1985 12–3/4 (324)
300 Tempest AK 1986, start 14 in. flywheel, full circle rear seal 14 (356)
HP320 EFI AK 1987–1989, Mercury Marine MPI intake 14 (356)

 

GM V8 350 cid (5.7L) with Roller Lifters - Sterndrive Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
5.7L CD 1991–1993, start GM hi–rise intake, Bravo only 14 (356)
5.7L MD 1993–1995 14 (356)
5.7L MJ 1997, 7MJ, start GM 2–bbl intake 14 (356)
5.7LX MD 1996–1997, start GM hi–rise intake 14 (356)
350 Mag CD 1991–1993, start GM hi–rise intake 14 (356)
350 Mag MD 1993–1997 14 (356)
350 Mag MPI MH 1995, start MerCruiser MPI intake, Bravo 14 (356)

 

GM V8 350 cid (5.7L) with Roller Lifters - Ski Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
5.7L MJ 1997, 7MJ, GM 2–bbl intake 14 (356)
350 Mag CD 1991–1993, start GM hi–rise intake 14 (356)
350 Mag MD 1993–1997 14 (356)
350 Mag MPI MH 1995–1996, start MerCruiser MPI intake 14 (356)

 

GM V8 350 cid (5.7L) with Roller Lifters - Inboard Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
5.7L MM 1996–1997, start GM hi–rise intake 14 (356)

 

GM V8 350 cid (5.7L) Gen+ - Sterndrive Models (LH rotation), with roller lifters

Model GM Code Comments Flywheel Diameter in. (mm)
5.7L MH 1998–2002, start MerCruiser 2–bbl intake, 0MH, startToluca production 14 (356)
5.7L MN 2002–UP, MerCruiser 2–bbl intake 14 (356)
5.7L EFI MH 1998–2002, (TBI), 0MH, start Toluca production. 14 (356)
5.7LX EFI MH 1996–1997, 6MH, start Gen+, Bravo (TBI) 14 (356)
350 Mag EFI MH 1996–1997, 6MH, start Gen+, Alpha (TBI) 14 (356)
350 Mag MPI MH 1996–1997, 6MH, start Gen+, Bravo, start MerCruiserMPI intake 14 (356)
350 Mag MPI MH 1998–2002, start low MerCruiser MPI intake, 0MH,start Toluca production 14 (356)
350 Mag MPI MN 2002, low MerCruiser MPI intake 14 (356)
350 Mag MPI MN 2002–UP, start GM IAFM (GMEFI) intake 14 (356)

 

GM V8 350 cid (5.7L) Gen+ - Ski Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
5.7L MH 1998–2002, start MerCruiser 2–bbl intake, 0MH,start Toluca production 14 (356)
5.7L MN 2002–UP, MerCruiser 2–bbl carb intake 14 (356)
350 Mag EFI MH 1996–1997, 6MH, start Gen+ (TBI) 14 (356)
350 Mag MPI MH 1998–2002, start low MerCruiser MPI intake, 0MH,start Toluca production 14 (356)
350 Mag MPI MN 2002, low MerCruiser MPI intake 14 (356)
350 Mag MPI MN 2002–UP, start GM IAFM (GMEFI) intake 14 (356)
Black Scorpion MH 1996–2002, 6MH, start Gen+, MerCruiser MPIintake, 0MH, start Toluca production 14 (356)
Black Scorpion MN 2002–UP, MerCruiser MPI intake 14 (356)

 

GM V8 350 cid (5.7L) Gen+ - Inboard Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
5.7L MK 1998–2002, start MerCruiser 2–bbl intake, 0MK, startToluca production 14 (356)
5.7L ML 2002–UP, MerCruiser 2–bbl carb intake 14 (356)
5.7L EFI MK 1997, (TBI) 14 (356)
350 Mag MPI MK 1998–2002, low MerCruiser MPI intake, 0MK, startToluca production 14 (356)
350 Mag MPI ML 2002, low MerCruiser MPI intake 14 (356)
350 Mag MPI ML 2002–UP, start GM IAFM (GMEFI) intake 14 (356)

 

GM V8 377 cid (6.2L) Gen+ - Sterndrive Models (LH rotation), with roller lifters

Model GM Code Comments Flywheel Diameter in. (mm)
Scorpion 377 MH 2000–2002, Bravo, MerCruiser MPI intake, this modelonly built by Mercury Racing 14 (356)
Scorpion 377 MN 2002–UP, Bravo, MerCruiser MPI intake, this modelonly built by Mercury Racing 14 (356)
MX 6.2 MPI MH A 2001–2002, Bravo, start low MerCruiser MPI intake,built by Mercury MerCruiser, P/N 431–862562camshaft 14 (356)
MX 6.2 MPI MN A 2002, Bravo, low MerCruiser MPI intake, with P/N431–862562 camshaft 14 (356)
MX 6.2 MPI MN B 2002–UP, Bravo, start GM IAFM (GMEFI) intake,with P/N 431–862562T 1 camshaft 14 (356)

 

GM V8 377 cid (6.2L) Gen+ - Ski Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
Scorpion 377 MH 1997–2000, MerCruiser MPI intake, this model onlybuilt by Mercury Racing 14 (356)
Black Scorpion MH A 2001–2002, start MerCruiser MPI intake, built byMercury MerCruiser, with P/N 431–862562camshaft 14 (356)
Black Scorpion MN A 2002, MerCruiser MPI intake, with P/N 431–862562camshaft 14 (356)
Black Scorpion MN B 2002–UP, MerCruiser MPI intake, with P/N 431–862562T 1 camshaft 14 (356)

 

GM V8 377 cid (6.2L) Gen+ - Inboard Models (LH rotation)

Model GM Code Comments Flywheel Diameter in. (mm)
MX 6.2 MPI MK A 2001–2002, start low MerCruiser MPI intake, built byMercury MerCruiser, with P/N 431–862562 camshaft 14 (356)
MX 6.2 MPI ML A 2002, with P/N 431–862562 camshaft 14 (356)
MX 6.2 MPI ML B 2002–UP, start GM IAFM (GMEFI) intake, with P/N431–862562T 1 camshaft 14 (356)

 

Go Directly to the Small V8 Longblocks in the Store.........Small V8 Marine Longblocks

Tuesday, November 20th, 2012

Marine Engines