The LHD Morris Minor had an unusual front cover on the ribcase gearbox from the factory. The casting number should be 22G124 and you're correct, the arm pivot area is wider than all other front covers. The reason for this was to make room for the stud and nut that come through this area just below the pivot. It's to maintain the bolt pattern in the bell housing without needing a special bell housing just for the LHD Minors. The fork should be correct as all of the ribcase types are the same on Morris Minors and Spridgets but the 22G124 cover needs a spacer tube and a longer bolt to secure the fork in the wider space. Take a look at the link below and scroll down to the picture of the 1098cc Morris Minor fork that shows the bolt and the aluminum spacer tube attached:

https://www.gerardsgarage.com/Garage/Tech/TO_Bearings/tobearings.htm


If your spacer was lost, you need to make a new one. It shouldn't be too difficult with some aluminum bar stock. Make sure to cut it to length so that it keeps the fork pressed up against one side of the pivot towers (where the fork is centered over the input shaft) and there's no free play when it's bolted together.

I hope all of that makes sense.

 But since doing the video, I have heard from a number of folks who say the cover doesn't matter, just the fork and release bearing type (and the thicker engine backplate). But, it is true that the pivot point will be slightly different. The jury's out as to whether this actually makes any difference or not - some claim it does, other's say not. I heard some old racecar drivers claim they don't change the ribcase boxes at all but just put the thick backplate on a 948 and that's it. It's just not something I've verified myself. So while using the ribcase front cover probably works, using the correct smoothcase cover, release fork and release bearing with the clutch package they were designed for is probably the best way to go especially if, as you mention, you're not doing the work yourself but paying to have it done. But the 1275 backplate will need to be used for sure. While it's possible to mate the ribcase to the thinner 948 backplate (as I did in the video) if the pilot bush in the back of the 948 crank is worn out - a properly installed new pilot bush seems to prevent this. The fitment doesn't really work without using the thicker backplate the ribcase was designed for. I only noticed later after the video was done that the pilot bush in the engine you see in the video was actually coming apart and that probably explained why the input shaft was able to go that far into the back of the 948 crank. At some point I plan on re-shooting that video and making a few of the points more clear. 

Ant any rate, we do offer the smoothcase covers machined for the shift rod(s) and installed with a rubber seal. And yes, when these are used it's best to drill the bell housing for the two holes at the top for the studs which are missing. Right now we'll need to locate a couple of more front cover cores to send off for machining, however. You could send me your smoothcase cover for modification if you're in hurry. Otherwise it may take some time to locate more cores.

There is one more idea I may suggest if maintaining some originality is part of your goal. There's a place in the UK called Heathrow Transmissions that can put the ribcase internals inside a smoothcase box. The thick backplate is still fitted on the engine but outwardly these appear more original than ribcase. Just a thought.

We don't have any covers as all of the last covers we had are sold. So, we'll need to see if we can get more soon.
But, your plan will work. However, it's imperative to use the ribcase shift lever on the ribcase box otherwise it will not shift correctly. We don't sell them as we need them for the rebuilds we do here.

Spridget Mania Tech Team

The Spridget Parts and Accessories Experts