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Hi folks, the 1071 rebuild continues. The shell is about to arrive. I have 2 gearbox casings to choose from. 22A1288 and 22G68. Both are 3 synchro and I have a straight cut set of gears to go in. I reckon the 22G68 is more "original" and older. But were there any changes/improvements in the later 1288 casing? I'm not terribly worried about authenticity because I don't have the proper 190 casing. What are your thoughts?

According to my gearbox fitment manual the 1071 should have a 22G190 of which there are 2 variants according to engine number. Do you have the engine number?

The 22G68 was the standard gearbox for the Cooper, the 1288 is a much later 3 synchro box.

The 1288 is probably a "better" stronger gearbox than the 68, but as you already know, neither are really correct for your car, not that that should be a deal breaker on a user.

Check out the gearbox info here:

https://mk1-performance-conversions.co. ... anical.htm

My 1071 engine currently has a factory gold seal 1288 gearbox with A type S gears. This was fitted to the car it came out of at least 40 years ago.

My 1275 Cooper S also has a 1288 A 3 syncro box from a gold seal engine replacement. Almost all new gears
in the rebuild last year. Some of the S gears I can't seem to find anymore. While mine was apart, I upgraded
the engine to gearbox mounting bolts from 1/4-28 to 5/16-24

Beware - the different gearboxes may have different sizes of bearings - the main one and the idler gear in particular.

When trying to put a later bulk ring cluster into an early cone synchro case, I ended up having to get the casings line bored to accept the larger bearings. This despite the parts manuals claiming the bearings were the same.

Thanks for your replies. I found the engine block in the boot of a mk3 that I went to look at. The guy had the 120 clock as well so all in all it was a good day's hunting. I didn't buy the car as it was too far gone. The engine number is 9F SA H 33001. It was completely standard so I got it bored to +20 and did the journals and got it line honed. So I don't have a 190 casing. I have the box nearly fully built using the 1288 casing and it's all fitting nicely. So based on your replies I think I'll leave it so. Many thanks. Doug.