Supercharger USA make the manifolds themselves - mines a two part, nice piece of kit. BDS also supply blower manifold for the 455ci. Both companies can supply complete kits. I'm still waiting for the ally vee pullies to bolt to the crank, once I have them I cannot wait to start her up. :TU:
Couldn't tell from the photo, but I hope you're going to be running an aftermarket balancer to drive that pulley for the blower. The stock rubber ringed balancer will not like life if its driving that pulley.