Early A Body Headers 273, 318, 340, 360

I've got a pair of rusty 360LA headers in a 1970 Duster, not sure they would fit, but I am about to pull the motor and replace it as well as the headers. They are no where near rusted through, about 14 yrs old with maybe 35,000 miles on them. 3" collectors. What can you offer and how long can you wait? It may take a month to get them off my car/start the work on it...
I have a set already ceramic coated, lightly used. Probably 15 minutes of run time before I pulled the engine. I went stock after reinstalled. $400.00

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