OMC Parts Drawing *Cobra *Mercruiser *Alpha SEI Outdrives
Mercruiser manifold V6 conversion kit 4.3 liter
Alpha One 4.3 liter V6 262 manifold 1 piece to
2 piece conversion set
Updated May 16 2026
- Complete conversion kit for 1 piece to 2 piece center rise manifold assembly
- For 6 cylinder 4.3 liter 262 CID models
- Includes port and starboard assemblies, risers / elbows, bellows and clamps
- Manufactured by GLM Marine with a 3 year warranty
- New design has more water circulation area for increased cooling
58992 Mercruiser conversion kit exhaust manifold V6
Included
- P/N 51220 Exhaust manifold assembly / 99746 A17 x 2
- P/N 51110 / 98504 A3 or 51140 / 807988 A2 Elbow (3 inch or 4 inch) x 2
- P/N 32170 Gasket / 27 – 99757 x 2
- P/N 30240 Gasket / 27 – 863724 x 2
- P/N 13991 90 degree hose fitting / 22-806926 x 2
- P/N 13992 Drain plug / 22 – 806608 A02 x 2
- P/N 80140 O ring for plug / 25 – 45253 x 2
- P/N 22391 Stud / 16 – 49545 x 8
- P/N 21248 Flange nut / 11 – 46335 x 8
- P/N 89120 Upper bellow / 32 – 44348T x 2
- P/N 89130 Lower bellow / 32 – 14358001 x 2
- P/N 01100 Hose clamp / 54 – 815504372 x 12
- P/N 50750 Exhaust tube / 14478 T01 x 2
Removing the Single Piece Manifold
- Removing the assembly, make sure to disconnect the battery from the terminals.
- Install the two piece assy.
- So the height of the elbow is a 1/2 inch lower.
- Refer to your Mercruiser repair manual to determine the ‘minimum’ riser height.
- If not above the minimum height a spacer can be put in place.
Raise it up to meet OEM spec. - Start by removing all the parts and mounting hardware (keep these).
- Disconnect the water hose which is connected underneath, and remove whole assembly.
Exhaust Conversion
Installing the 2 Piece Assembly
Wipe down all mounting and connecting surfaces of all pieces to ensure they are clean and free of oil or grease.
- Start by installing the new water hose fittings into the new assembly, with the openings facing towards the front of the boat, pointed slightly outwards by a few degrees. Install the gasket, and torque the mounting screws to 33 ft.lbs or 45 Nm.
- Next, install the starboard (right side) water hose with the clamp firmly tightened. You’ll need to route the port (left side) water hose underneath the power steering pump onto the fitting for the hose, and secure the clamp tightly.
- Check the condition of the water shutters (flaps)
- Install the plugs into the new elbows.
- Make sure to apply a sealant or thread locker onto the main bolts connecting the manifold to riser, and torque these to 33 ft.lbs or 45 Nm
- Connect the upper bellow
- Followed by the curved elbow tube
- Lower bellow using the included clamps.
Photo
Description / OEM #
Price (USD)
Price (Canadian)
51220 GLM
P/N 51220
Exhaust manifold assembly
(1983 up),
serial numbers
6330183 – up.
99746 A17
$218.95
$ 375.89
51140 elbow
$143.95
$ 268.89
89130 Mercruiser exhaust bellow
P/N 89130
Lower 4″ bellow
32 – 14358001
$32.95
$ 45.89
01100 Hose clamp
P/N 01100
Hose clamp
54 – 815504372
13990
drain plug kit
P/N 13990
Hose fitting with drain plug kit. Includes 90 degree hose fitting, drain plug and o ring.
22 – 806926 A1
$6.95
$ 11.89
22381 Mounting screw
$4.95
$6.89
22391 Threaded stud
P/N 22391
Steel stud, thread on both ends (used for P/N 51110)
16 – 49645