Glad to see your still at it with your truck. Sorry to hear about the soaked brake linings. I've done a bit of web searching tonight and can't find any sources for lining kits (original GM# 605380) or lined shoe replacements (original GM# 3660048).
You might try to check out local big rig truck shops that may be able to reline those, or at least give you a lead on a clutch and brake relining shop. IIRC, the linings are 3" w x 16" long.
