E-bay would be another source.
I found some correct baby moons at a used hub cap store. They did not know what they had. They were OEM caps. The store thought they were some aftermarket pieces and were priced very low. Give the web a search. It is time consuminghowever in manny cases will produce results.
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!