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Five-speed gearbox conversion kit for MGBs

Published 18 January 2017

A new five-speed gearbox conversion for MGB owners is being offered by parts stockist British Motor Heritage. The kit requires no bodywork modifications and costs £2490, including VAT.

Based on the transmission from the Mazda MX-5 Mk3, the Vitesse Global five-speed manual gearbox conversion comes fully assembled and complete friction plate, slave cylinder, braided clutch pipe, speedometer cable, prop’ shaft and fixing kit.

Fitting it should make any MGB feel more at home in modern traffic. It also promises to create a smoother gearchange and the short-throw ’box is ideal for drivers looking to press on thanks to a better gear ratio spread. It's also said to be quieter than a Type 9 or MGB box and comes with 60,000 mile service interval. With a high torque capacity, it can even be fitted to a V8.

However, it's still one of the most expensive kits out there. A BMH spokesman said, 'The Type 9 kit doesn't include a gearbox, and a good refurbed unit is getting on for £1000. Add to it the £850 for the kit and you're getting close to the cost of our kit - but you get a brand new gearbox rather than a refurbished one.'

John Yea , BMH’s managing director, said, ‘We have tested this product in a wide variety of conditions and it performs as though it was made for the MGB; not least because the final drive ratios of the four-cylinder MG and Mazda MX-5 are the same.’ Find out more at

BMH MGB 5 Speed

The BMH five-speed kit is based on the gearbox from the Mk3 Mazda MX-5.



John Searby    on 20 January 2017

What makes even more sense is to fit a complete Mazda MX5 engine and gearbox.

anglebox    on 20 January 2017

It's a tough one isn't it? I mean, where is the line between improving performance and losing the car's soul. It's one thing uprating a gearbox from a later example used in a model (eg swapping a four-speed to a four-speed plus overdrive) - but if you change the engine and the gearbox completely then there won't be much of the original car left. Don't get me wrong - I'm not knocking anyone that does (it's their classic and they can do what they like with it), I'm merely interested to start a conversation and find out the views of others.

Edited by anglebox on 20/01/2017 at 15:23

Paul Milsom    on 22 January 2017

Once you start changing major components, the whole point of the car is lost, I run a peerless gt with the 1991 cc tr3 lump. it's all standard , I could uprate it to 2138cc TR4 spec. , but it's not original, or at least in the spirit of it. . like "hotrodding" a car swop the chassis, motor/trans undercarriage etc, then call it a .. 32 chevy or whatever.. is rubbish. Its my "grandfathers axe" my father changed the head, I changed the handle...

Dennis Humphrey    on 14 May 2019

The point is these cars are little boys toys and us little boys like our toys to be different to other little boys toys.

Dr. James Moran Fretwell    on 22 September 2021

No one except the owner knows what lies blow the surface.

Therefore it is a trade off between a better, smoother performance, and maintaining the original spec to the absolute hilt.

I have a 1980 MGB LE roadster Federal SPEC, which was encumbered with all that exhaust emission rubbish required on the American version (I bought my car in New York.

Straight in the bin; not in the slightest concerned with maintaining the original.

My MG was completely renovated from a bare shotblasted shell upward, and I replaced everything with the new.

There were 3 piles, 1 was all the rusted stuff, 2 all the stuff for chrome and cadmium plating, and 3 the stuff which was OK and simply went back on the car.

Who knows but me, and the chap who did it all.

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