Choice of gearbox

The Magnette was never offered with the option of overdrive although it can be fitted: see separate article). Just as a more powerful engine can make the Magnette more suitable for modern use, the addition of overdrive or a five-speed gearbox brings considerable benefits in economy and flexibility. What follows is a consideration of the wider gearbox options with and without overdrive.


Until the introduction of the 1622cc MGA Mk II, gearboxes in the Magnette and MGA were fundamentally the same and a standard Magnette box will fit and cope with the extra power output. Even the 1622 gearbox brought only minor modifications, so it is not a radical departure from standard. However, if you are fitting an MGB engine then it makes some sense to fit the corresponding MGB gearbox. The earlier B box offered synchromesh on the upper three forward gears whilst the later version included it on first gear too.

As with engines, for the adventurous with no limitations on cost or engineering skill, the choice is very wide. However, for practicality and relative ease of installation only the 3-synchro box is worth consideration. No Magnette driver is likely to be over-worried about having synchromesh on first gear and the earlier box still offers the advantages of strength to handle the 1800cc output and the availability of the Laycock de Normanville overdrive.

With different gearboxes, the challenge is to fit them in the transmission tunnel with the gear lever in the right position in the cockpit. The original lever hole in the tunnel may need to be enlarged to accommodate a different remote control extension and the lever may need bending or adapting so that it falls to hand. Some conversions require a bit of mild "metal-bashing" in the tunnel to make them fit.

There is no reason why an MGB engine cannot be combined with the 5-bearing High-Gear Sierra gearbox conversion but you would need to speak to High-Gear to be sure of getting the right combination of bell-housing and other components to fit the Magnette. The key issue is to have the starter positioned so that it does not foul the steering column on RHD cars. This affects the gearbox but also the choice of engine back-plate that it mates to.

I believe that because Datsun and Nissan as it later became used designs that were based on Austin-Morris originals, there are gearboxes from their contemporary models that will fit or can be adapted. This is a more common approach in Australia where there is a better supply of relevant parts. Contributions based on real experience of such conversions would be welcome.

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