Here some pictures and info on correct colors for a restoration of the early Ford Mustang six engines. Ford painted the assembled Engine long-blocks, IE block, head, and oil pan, all Black through end of 1965 year models, this included paint covering all the hardware (bolts etc). The valve covers were painted separately from the engine their color is one way to ID the engine size. The Valve Covers were installed near the end of engine assembly using natural metal bolts with special integral lock washers.
This is a 170ci six cylinder base engine as used in the 1964 1/2 Mustang's in the first 5 months of production. Info I have says it has a red valve cover and air cleaner but I remember them being more of an Orange as were the early 170 Falcon motors. The Valve cover bolts are a natural metal.
1964 1/2 Mustang 170 six Engine Color Reference
Engine/Part Color
170ci valve cover Red ?
170ci air cleaner Red ?
170ci block, head, oil pan Black
Here pictured is a 200 six now the standard engine for the 1965 Mustangs. Looks much the same as the 170 it replaced, with the red valve cover and air cleaner. Valve cover bolts are natural metal.
1965 Mustang 200 six Engine Color Reference
Engine/Part Color
200ci valve cover Red
200ci air cleaner Red
200ci block, head, oil pan Black
The 1966 and later Ford engines were no longer color keyed to specific models all Ford engines were now painted Ford Corporate Blue (Dark Ford Blue). This was the new color for all Ford engines for 1966 and later. As before the entire Engine long block was painted after it's assembly and the valve covers were painted separate and than installed on the engine with the same natural metal bolts with the special integral lock washers as before.
This is the 1966 200 engine the air cleaner is made a little different from the 64 1/2 and 65 engines. Ford engines were now painted in the Dark Ford Corporate Blue starting in 1966, Valve cover bolts are the natural metal. The Sports Sprint models have a chrome air-cleaner housing, as did the 1966 Sprint 200, made available during Spring 1966.
1966 to 1973 Mustang 200 six Engine Color Reference
Engine/Part Color
200ci valve cover Dark Ford Corporate Blue
200ci air cleaner Dark Ford Corporate Blue
200ci block, head, oil pan Dark Ford Corporate Blue
The 1969 to 1973 Mustang 250 six Engine was also painted the same Dark Ford Corporate Blue