Hey Ferndale53-
The flywheel will have holes drilled to fit only the one size pressure plate (~12" apart) so you really can't use a smaller clutch unless you get a different flywheel too. The 11" clutch is the heavy-duty version used on commercial and some 4-speed trucks. I've seen several outfits that sell a new 11" clutch kit (no core charge!), and I know that Jim Carter Classic Truck Parts does sell refurbished 11" disks and pressure plates (with core charge).
Have you had the flywheel resurfaced yet? I'd do that first because if you have hot spots, etc the flywheel may be out of limits and you'll have the pleasure of finding a different one anyway. The resurfacing has to be done with a proper flywheel grinder, preferably by someone in the business. (I had a chum with a brake lathe turn mine, and the hot spots were breaking lathe bits and it didn't come out flat. I could see the last mechanic's finger prints beautifully immortalized in steel as hard hot spots that now stood up above the rest of the surface.
When you do order the new clutch kit, make sure you verify with the vendor that the new pressure plate hole number/spacing matches up with the flywheel, that the disk has 10 splines, and the throw-out bearing is the 1-7/8" deep model. I agree with 3B- there is no problem with having a big clutch- they grab better, slip less, and last longer.
When you install it, treat it like a brake job- clean everything spotless with brake cleaner, and leave absolutely no fingerprints.
