Where would I get a 9" 26 spline GM clutch? I am putting a bit of a ******* combination togethere (67' 230ci six, ST10 with 3.42 first gear) and need to find a 9.12"/26 spline clutch to replace the stock 10 spline one.
Find a local clutch builder and ask them to re-hub one for you. It's a common trick for the stove-bolt T5 swap. They are switching from 14 to 10 spline, but it's the same operation. http://www.inliners.org/Jack/Robt_french.htm
Yes, you will need to have a clutch and brake shop use the hub from one disc and mate it to the smaller disc. There might be something available in the multi clutch disc racing units but they are probably expensive?
I think I may have found one in an OEM. 94-2002 S10 with a stick and a 4.3. They have a 9 1/8" clutch with a 1 1/8" 26 spline hub.
You won't believe this one. Try Lawrence Transmission in Rexdale. They have a huge stock of NOS parts from the 30's to 80's. Ask for Chris The Old Tinbasher