Building a Triumph Spitfire For Performance


because the triumph gearbox is noisy, not all that strong and the overdrive saps power. Need I say more?


After getting through several gearboxes I  decided to fit a Ford type 9 also known as type N gearbox using a kit purchased from a UK company called Frontline (link at bottom), an MG specialist. The kit I bought comprised of an adapter plate, prop shaft, gearbox mounting, clutch friction plate, spigot bush and speedo cable. I could have bought a reconditioned gearbox from them but I opted to source my own. Instructions come with the kit. these are quite good but have no diagrams, and there are a few bits in had to work out for myself that I will divulge here.

  The Key to this conversion is this adapter plate which bolts the triumph bell housing to the ford gearbox, it is very well made!

The prop shaft, notice the end that 'plugs into' the gearbox

Here the adapter plate is attached to the bell housing, you have to drill to holes in the bell housing, the adapter uses 3 of the original holes. The 2 extra hole are at the top, close to the existing holes, I had  to fettle the area around my new holes so the bolts would sit nicely. I also had to add a couple of washer to these bolts otherwise they would have poked through the other side, and not allow the adapter to sit properly on the gearbox. You also have to remove some bell housing  material where the clutch cylinder sat, the clutch cylinder goes through the adapter plate hole and is retained by a larger grub screw.

Another thing you may need to do is open out the release bearing sleeve as it may not fit over the ford input shaft. I used a power file to enlarge it.

Triumph spigot bush on the left, modified bush for the ford box on the right

The ford release bearing sleeve has to be cut down as shown in the picture
Here it is all assembled, looks very tidy!

Installation is just like putting a normal gearbox in. I forgot to take pictures of the mounting plate, the triumph mounting base plate is removed and the supplied plate is a direct replacement. the gearbox is then bolted to the  new base plate via a sturdy rubber and metal block. Notice I had to cut away the tunnel to allow for the extra length. The supplied instructions don't mention this, but they do say that you may need to shave a little off the insides  of the chassis runners if the gearbox fouls, I had no such problem.

This shows the original long ford gearlever and the same type of gearlever after I heated up the rubber joint in the middle to separate the long bit of the lever from the main body. I then had to grind off a metal sleeve that remains. this leaves a nice stubby gear lever!

Here is the result after I modified a fibreglass gearbox tunnel with some thin aluminium sheet I had.

The install took a day and a half to complete and was a relatively trouble free and straight forward task. I decided shorten my clutch release rod because the clutch cylinder did no go far enough into the adapter plate hole for my liking.


Wow, its lots quieter and the gear change is so precise. 5th gear is so nice, no more 4000rpm motorway trips!! The car feel more solid too, the way the new gearbox is mounted is much firmer so there is a lot less movement. I wish I had done this ages ago!!

This kit is available from frontline    please mention my site when contacting them, thanks.