Mercruiser Alpha 1 upper gearcase and gear ratio

GLM Marine aftermarket outdrive upper gearcase
housing and parts

Last updated on 12/08/2023, 01:17:46

  • Replacement complete upper drive shaft housing for Mercruiser 1/R/MR/ Alpha one outdrive years 1970 to 1990 *No core required
  • Includes long yoke (drive shaft), U-joint and socket
  • See our upper gearcase drawing page for photos and a list of all the internal parts and components included
  • Serial #6225577 and up
  • All gear ratios are available, refer to application chart below.
  • Tech support exploded view drawings

GLM

OEM

Ratio

Engine

19100

1547-9421A20

1.50/1.47 (20/22)

MOST V8 UNDER 300 HP

$1199.99

19200

1547-9421A21

1.65/1.62 (24/24)

6 CYLINDER INLINE

$1357.95

19300

1547-9421A22

1.84/1.81 (17/19)

V6 & 470/485

$1199.99

19400

1547-9421A23

1.98/1.94 (20/24)

4 CYLINDER INLINE

$1375.95

19500

1547-9421A19

1.32/1.30 (16/20)

V8

$1313.95

Customers who bought P/N 81390 also purchased:

87510 Mercruiser seals gasket kit 26-33144A2

P/N 87510 seal kit for Mercruiser lower units 1970 – 1990 models.

Replaces Mercury 26-33144A2. $42.95

21950 Bellows 30-803097T1

P/N 21950 For 1970 – 1990 Mercruiser models with serial numbers 3469428-0D46985. $145.95