In restoring my 67, these were my resources for parts:
Mike Guarderas, Washington state, parting out a Stout:
msg815@yahoo.com
Mike Bingham, Cabe Toyota, California, good source for OEM/NOS:
mbingham@cabetoyota.com
Carlyn Dinkler, North Carolina, THE expert on 1965-70 Corona RT43/52, the 1969-72 Corona Mark II RT6#/7#, and the 1970-73 Corona RT8#/9#. A bunch of these parts work with 3RB, and I am guessing they may share clutches. He stocks and refurbs old parts. He also stocks engine labels.
cdinkler@bellsouth.net
Rick Dormoi, (Pennsylvania?), is a good source for hard to find parts, including suspension.
rick@toyotaheadauto.com
Salsipuedes Auto Wreckers, Watsonville California. They have a number of stouts they are parting out, including interior parts.
They are on Facebook and have some Stouts featured.
https://www.facebook.com/SalsipuedesAutoWreckers
Phone: 831-728-1551. They don't seem to mind going out to the parts trucks and checking for even the most obscure part.
GWS RareParts. Good source for NOS on Ebay.
http://www.ebay.com/usr/gws-rareparts
Finally, Kurt at CruiserOutfitters is also a Stout guy and may be able to hook you up with a clutch.