You may be interested in a paint being sold as ceramic paint by EASTWOOD, It looks nice and dark and is listed as Chevrolet Gray but the picture shows what looks like a SBC valve cover, I'll see if I can pull up a picture....

EW Ceramic Engine Paint Chevy Gray Qt.1929-52
Item #51625 ZP
Only $32.99
Eastwood's Ceramic Engine Enamels provide a beatiful factory look finish that is super-durable and will withstand tempertures up to 650F. Developed using the latest ceramic nano-technology integrated with silicone alkyds, this is the new standard in engine coatings. Each color is replicated after the original color for that deep rich factory look. The ceramic nano-technology ensures that your motor will be protected and resist small chips, chemicals and heat. In fact this is the highest temperature range in the industry, 650F! NOT FOR USE ON EXHAUST MANIFOLDS OR HEADERS
BUT the info says it is
NOT for Exhaust Manifolds Check out some of their powder coat paings.