MGA Gearbox Conversion Kit 5 Speed Mazda


Prices are exclusive of VAT

Built to order - Despatched 10-15 business days after order receipt
Product code VITMGA255


  • Fits exactly in place of your existing gearbox
  • Improves feel and power delivery
  • Reduces weight
  • Comes fully assembled
  • Gear ratios suit perfectly
  • Easily fitted by anyone who could fit a standard MG gearbox
  • Full fitting instructions provided
  • Optional electronic speedometer
  • Period correct gear knob
  • Electrocoated parts


  • Gearbox fitting service available in the UK
  • Worldwide shipping
  • 12-month parts defects warranty
  • Suitable for all MGAs including 1800 conversions
  • In the USA or Canada? Visit our North America distributor Moss Motors


At Vitesse Global we ship our MGA gearboxes right around the world, delighting MG owners from the UK right to the USA, Canada and Australia. 

Our gearboxes offer the ultimate upgrade for your MGA, improving your driving experience without losing the sense of history and character you love.


What’s in the kit?

  • NEW Mazda MX-5 5 speed transmission with:
    • Vitesse gearbox case
    • Vitesse bellhousing
    • Vitesse machined billet front plate
    • Modified rear case with Mazda mechanical Speedo drive assembly
  • Mazda MX-5 OE clutch friction plate
  • Bespoke shift lever and shift knob kept in original position
  • Concentric slave cylinder assembly
  • Braided clutch pipe and remote bleed pipe for easy bleeding
  • Prop shaft
  • Spigot bush with Mazda OE needle roller bearing assembly
  • Speedo drive cable
  • Gearbox rear mount bracket Assembly and Isolator
  • Complete UNF fixings kit
  • Clutch alignment tool
  • Diaphragm spring clutch cover assembly in all MGA 1500 and 1600 kits
  • Aluminium backplate in 1500 kits
  • Clutch master cylinder in Twin Cam / Delux kits

Do I need an electronic speedometer?

We include a mechanical speedometer sender and cable in your kit as standard, which fits to the original instruments in your MGA and does everything you need it to but if you are looking to improve more than just your gear selection and power delivery, we offer a Smiths electronic speedometer.

  • Easy to install
  • Easy calibration
  • Saves on both cost and time of sending original mechanical speedo away to be re-calibrated
  • Bouncy needle issues eliminated

For more detail on speedometer calibration and a handy calculator, click here

What’s in the Smiths electronic speedometer kit?

  • Mazda electronic sender unit fitted to the gearbox in lieu of the mechanical one
  • Wire harness with dedicated connectors at either end to connect to the sender and instrument
  • 4” (100mm) instrument for MGA and all chrome bumpered MGB’s. Note: Only suitable for negative earth vehicles and cannot be switched


Can I fit the kit myself? 

Yes! Anyone mechanically confident enough to remove and install a standard MGA gearbox will have no trouble fitting one of our kits, as everything has been specifically designed to match your vehicle - no need for any bodging at all! 
If, however, your mechanical skill stops short of gearbox installation, we’ve got you covered. We can deliver your new gearbox straight to your chosen mechanic and speak directly to him (or her), should they have any questions regarding the installation.

If you are still unsure, take a look at our installation instructions


A word from Alec Poole, Vitesse Sales Manager, Sixties MG Engineering Apprentice and Works Race Driver

"With lifting equipment, the easiest way to fit our MGA 5-speed replacement gearbox kit is to remove the old gearbox with the engine. Should the floorboards have been removed in the last 10 years, an alternative way is via the cockpit, leaving the engine in-situ.

Any competent Fitter can undertake this work. If your kit does not fit easily we suggest you seek professional help. Remember all MGA’s are in the region of 60 years old. It is not necessary to bodge your pride and joy to fit our kit."


Reviews and features

We're under no illusions, our gearboxes aren't cheap, we're OK with that. We are also entirely sure they represent incredible value for money and brilliant British build quality - but we would say that. Instead of listening to us, take the word of some of the biggest names in the MG world: 

MG Enthusiast feature

MGCC feature


Want to lighten the load? 

Our all-alloy case means significant weight savings can be achieved with this kit, up to 13.5kg compared to the MGB Overdrive box! 

MGA gearbox kit weights

The perfect ratio: 

The standard MGA gearbox differential has a ratio of 4.1:1, similar to that of the MX-5 differential, meaning the gear ratios work perfectly in the MG. Furthermore, the standard gear ratios of the Mazda gearbox are similar to the Ford Type 9 close ratio gear set, which attracts a significant premium over the standard Ford Type 9 gearbox!

Gear Ratio - Mazda Transmission 
1 3.136
2 1.888
3 1.330
4 1.000
5 0.814


Still unsure about upgrading? Ask us anything! 

We get all kinds of questions about our gearboxes: ‘will it fit x?’ ‘what about connections to this or that?’ ‘can I fit your gearbox to Y?’. Some people who contact really do know a quite astonishing amount about both their car and our gearboxes but other are happy just to know it will work and want to know about bout Vitesse: who we are, how helpful we will be etc etc. Whether you’re super technically minded or really don’t know a spline from a bellhousing and want a gearbox shipping straight to your mechanic, we’re here to help!

Get in touch on:
Tel: +44 (0)1455 611230

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