FIVE-SPEED AHEAD
Converting a classic to a motorway-friendly five-speed box is a common mod these days, but what’s involved?
I n terms of mainstream cars the five-speed gearbox was something of an ’80s phenomenon and now of course six is common, with the latest automatics routinely sporting eight.
The Italian makers notably provided five-speed boxes earlier than most but back in the ’50s they were virtually unknown and even in the ’60s it was generally only the preserve of cars with sporting pretensions. Overdrive was generally preferred by the British makers and in the pre-motorway era the lack of a high-speed cruising gear wasn’t really an issue for most drivers of average saloons.
Fast forward a few decades though and many classic car owners these days really like to use their cars for longer trips, which generally means dicing with traffic on dual carriageways and motorways. As traffic speeds have become higher, just keeping up with the flow can be hard work, not to mention a strain on an older engine which wasn’t designed for constant high revs.
Which is where the five-speed conversion comes in. Yes, many classics can be transformed simply by swapping a four-speed for a five-speed unit from the same maker and if you’re lucky then it will be a simple bolt-in job. Even things like speedometer drives can usually be worked around these days thanks to the plethora of aftermarket solutions and general ingenuity of the classic car scene.
But what do you do if your car was made before the idea of a five-speed box had entered the consciousness of the general motoring public?
The solution is likely to be found in the shape of the good old Ford Type 9, the five-speed unit fitted to the Sierra among other things. A robust and compact unit, it’s easily modified to suit many older cars – most of them non-Ford – and various firms can now offer bolt-in conversions for everything from Minor to MGA.
One of the most well known of these firms is Hi-Gear Engineering which was born when proprietor Peter Gamble modified a Toyota gearbox to fit his Morris Traveller. When he later came to upgrade an MGA it was the Ford Type 9 which proved to have the ideal dimensions and could be fitted with the minimum of modifications to the original car. To cut a long story short, the Ford box was modified to fit the bellhousing and tail of the MG layout and a new crossmember was fabricated to suit the new gearbox as a bolt-in part.
Business for Hi-Gear started from there and the same basic approach is used for all the five-speed conversions on the market: the five-speed unit receives a bellhousing to bolt up to your existing engine, while the rear of the new box is also modified to suit the existing propshaft. In extreme cases the opening for the gearlever may need to be modified but in most cases a revised lever can do the job. The aim is very much to produce a bolt-in conversion which can be reverted to standard if required... although having tried both Midget and MGA with the five-speed conversion I know it’s not something many owners would want to do.