Best place to purchase Headers

Dougs D453 will fit with no issues?? 73 Duster Colum Shift, and also 6 to V8 schumaker conversion mounts. another question how is the installion, installing with engine in installing from underneath.1970Duster that is good price and summit is the route i will take but i need reasurence with above questions. Are they coated or uncoated. Coated is what im looking for... Appreciate input.