I bought HP Fastener Set 8065C, c-body: Tom Hergert, 6901 128th Ave SW, Olympia, WA 98512. 7 nuts, 3 long and 2 short bolt head nuts, 12 studs, Rocket Restorations
Looks like Dante's has same kit
DMPS-6901-8065C Mopar Exhaust Manifold Hardware Kit 1968-71 C-body 383/440 HP - dantesparts.com