You can take it to your local machine shop and have it baked and shot peened (sp?). I took a grubby looking cast iron manifold off a SBC in and for $25 if came back looking like brand new inside and out.

The other option is to use the electorolytic rust removal technique described in the tech tips section. I've used it on manifolds before with pretty good results.


Daily Driver 63 C-10 LWB Fleetside