We always painted our engine compartments and race car interiors with gloss medium grey enamel back in the late 70s and early eighties...
It would look reasonably clean w/o scrubbing and the gloss surface could be wiped down quickly.
I remember seeing the the Huffaker Group 44 cars with their interior and trunks painted with "trunk paint"...white/grey splatter or "multifleck paint" made by "Zolatone." Durable fersure, but harder to keep clean than gloss.
If it's grey in the engine compartment, you can choose any exterior color you want -- even white -- and it'll still look good with a bit of road or track dirt on it.
Cheers!
Delia
_________________
1973 2002tii - gone
Inka (aka "Orange Julius")
VIN 2762756
1974 2002tii - gone
Polaris (aka "Mae West")
VIN 2782824
BMW CCA member #1974
www.oldschoolbmw.com
deliawolfe@gmail.com