Here are 2 photos that I swiped off Ebay of transmissions.... The lower photo seems to use a floor mounted shifter with a linkage rod...and the upper photo has the shifter mounting directly in the transmission housing.

What's the background on this? Are they interchangeable with any given body shell and/or subframe? Maybe I just can't see enough detail in the lower photo that is hidden by the subframe...but are these different?

 

The top photo is of an early gearbox. The long shift lever was called "Magic Wand" by the sales boffins at BMC. The second photo looks like a rod change gearbox that came on later Minis and used a shorter, more straight up shifter. The shift lever was connected to a rod that went into the gearbox. Rod change boxes are known for leaking around the rod seal. Coopers used a "Remote Control" gearchange. Straight up type shifter that was connected to long box with the shift linkage inside. Check out some of the vendor's catalogs for some good drawings of the gearchange assemblies used.

 

I don't believe they're interchangable... At least, I've never seen conversion kits for sale at any of the vendors (someone correct me if I'm wrong on that please). Rod change shifters are located further aft in the cabin, making for a more modern feeling, but people swear alternately by both systems.

Madoc is right about the rod change seal leaking but don't let that bother you too much - I had to swap out mine after owning my Mini less than a month but did so pretty easily. Luckily it's a really cheap kit (comes with a new seal and a special bushing and dust cover to keep everything aligned and in good shape) and is fairly easy to install with the right tools and a bit of spare time.

 

From what I've read, they are somewhat interchangable, but swapping from 1 type to the other involves cutting a new hole in your floor or firewall for the shifter shaft, plus installing the necessary gearbox mounting points.
It's not a straight swap, but it's far from impossible.

 

The magic wand comes out much closer to the firewall, so as Agro said you'll end up with a big hole!

Rod and Remote are *much* nicer to drive than the 'ole pudding stirrer that the 850s had.

 

The mini that I am looking into has the "magic wand" shifter and it is an 850.

 

I've been told that it truly is magic if you get it to slot into the right gear!

I like the idea of an early Mini - especially if you plan to preserve it as an example of the first of the breed. I'm told by people who know a lot more than I do that the later ones are easier to "improve".

 

how do I know which one I have?

 

Look under the car where the shifter linkage comes out the back side of the engine. If you see a metal box running the length of the linkage you have a remote tranny. If you see two rods, you have the rod-change. If you look in the car and you see the gear lever coming out of the firewall and then angling up you have the "magic wand" type.