Howdy John the engine bay is painted the same as the entire car. The colour is called Bondi Bleach the valve covers and air cleaner are powder coated a "safety yellow" colour which it makes it a tad darker than the original yellow.
I'm running a 2 bbl carter carby and manifold at the moment only because the 4 bbl Holley wouldn't accomodate the air cleaner.
The red colour for the engine is off a different year Valiant and the engine now runs a worked 265 ci and Borg Warner 35 tranny.
About 80% of the parts are NOS which took me over 20 years to collect but worth it. The pics are nearly 4 years old now and the engine bay looks even better now with more period right parts on her.
Hope this was helpful.
Cheers, Nick.