If you use a jeep 10 spline input shaft you could use the original disc.
The t-5 he has is 14 spline input shaft,so he had the clutch disc built for the conversion. no spacer plate or lengthening the splines are needed.Just cut the throw bearing collar and input shaft snout to length.
I used a similar spacer plate a friend machined, that also meant I did not have to lengthen the splines or shorten the input shaft. Also found an Astro van clutch disc. Love the T-5 in my 46 pickup.
I have run across several different solutions that people use to adapt an S10 T5 for use in their trucks. Not that any one is the best, but here is what I have read about. Each approach has a different advantage over the others.
1. Tom Langdon has advocated cutting a short bit off the end of the input shaft and then grinding out (or machining) a portion of each of the friction disc inner hub splines. That way the input shaft splines don't need to be lengthened.
2. The adapter plate is a one time expense and solves the problem plus you can sell it if you ever switch to an automatic (if you have a bad knee or hip for instance).
3. A V8 Camaro T5 and an Astro T5 have the correct length bearing retainer and correct length input shaft so no modification is needed. Just use the correct splined friction disc and throwout bearing. The Camaro T5 will need an S10 tail housing swapped so the shifter is in the forward position.
4. This next idea is perhaps new to some. Look at the photos of the V6 Camaro T5 I have. It has a 14 spline input shaft that is too long (same length as the S10 input shaft). However, the splines are cut all the way back to the bearing retainer and it has a short style bearing retainer just like the V8 Camaro and Astro T5s. I have not done anything to it yet, but hypothetically, simply nipping off the correct amount from the input shaft is all that will be needed. I'm pretty sure no adapter plate would be needed.
Also included are some side by side photos comparing the length of an S10 and V8 Camaro input shaft.
14 spline input shaft - 1989 V6 Camaro World Class T5 - photo 1 1989 Camaro - photo 2 Astro van Input shaft - 14 splines and no adapter plate needed V8 Camaro and S10 IS side-by-side More another V8 bearing retainer on the S10 input shaft Jay