Clutch plate splines - how many on a single reail gearbox?

[Toledo Man]

One of my local members (Kath) is in need of a new clutch plate on her immaculate 1975 1500TC. She tells me that the old one had 20 splines on it. Unfortunately, the one I have in my stash of spares is the 10 spline one. This 1500TC was built round about the time the Triumph changed over to the singe rail gear box.

Can anyone tell me how many splines the single rail box has? I can source a single rail gearbox clutch plate form Paddocks for £32.50 but I need to know if it has 20 splines or 10.

[cleverusername]

Just had a look in the garage and the 4 speed single rail off my 1976 1500 is definitely a fine spline, which would be the 20 spline one.

[Toledo Man]

I've gone back to my text message and Kath's is a 10 splines, not 20 (sorry, my bad). That means her TC has a 3 rail box. I'll need to recheck the clutch plate diameter.

Thanks for the reply.

[Toledo Man]

The part number for the clutch plate is GCP103. This should also fit the the 1098 MG Midget, the 1098 Austin-Healy, MK4 Spitfire and possibly some Morris Minors with the same engine as the MG & A-H. The clutch plate I have is 10 splines but is 6.6" in diameter (Borg & Beck HB8756). GCP103 is 7.25" in diameter.