I watched that Mark Worman guy on Graveyard Carz the other night. He spray-painted (hemi orange) a completely assembled 440-6 Pak engine (carb and distrubtor were not installed yet) hanging from a chain. Painted valve covers, all the nuts and bolts - everything. Even the HP exhaust manifolds were painted hemi orange. As he did it, he said that was the way the factory painted their motors. I was very surprised the exhaust manifolds were on the engine and they were painted too. . .
To this date I stand on the idea that the intent was to paint the engine, ie block heads intake etc, things like exhaust manifolds may have got overspray as they were installed at the time. Likewise with the fuel pump and the distributor.
I have seen where people painted the entire ground cable right up to the lug, maybe the first few inches might get paint as the painted the heads. On small blocks the bypass hose as well, overspray as needed to cover the areas of the timing cover that it crosses.
I have even seen alternator brackets and power steering brackets painted engine color? Only the bolts used to hold on the water pump have engine color as they are removed to put the brackets on and reused.
I sometimes thing the engineers didn't want paint getting in the openings so they chose to have the components installed
I follow what say the designers wanted and no engine color or overspray on the fuel pump, distributor, exhaust, hoses and cables.
The 273 prior to being installed in my Barracuda...
The interesting thing was for some reason the dipstick tube was put in after the fact and the dipstick was dipped in paint and hung upside-down so there should be a little paint nipple on the top of the loop.
Alan