I'm getting close to assembly on a 68 Olds 350. I see a lot of people meticulously mask and paint the block before assembly. Then fasteners, freeze plugs, etc... are not painted since they are installed afterwards. How did they come from the factory? It seems it would be easier to assemble the engine and paint just prior to installing accessories.

 

Prior to assembly opens you up to paint chips getting where they shouldn't be. Paint it after you get it together.

Also, who the hell wants to see freeze plugs? LOL

 

The engines were fully assembled with the exception of carb, distributor, etc and then painted on the way out the door of the engine plant.
The "accessories" ( carb, distributor, etc.) were installed on the assembly line.
Even the oil filters were painted engine color.

 

Yup, it was easy to tell if the oil filter was original, the outward facing portion would be painted engine color and the inward portion was the oil filter color as it was manufactured. Had one in the dealership that was obviously original by the two-tone paint with approx 22k miles, it probably weighed a couple of pounds.

 

I painted mine after assembly; it turned out well and it still looks very nice. I primed the valve covers and pan before assembly.

The only disadvantage was that the assembly required through degreasing with a mild solvent such as naptha before paint. A mild degreaser avoided softening any primer.

 

Do what you want. I think the guys who do it a piece at at time have a lot of time on their hands and might be a tad OCD lol.

 

It's called an undressed engine assembly, and the distributor and starter and if SMT the bell housing was installed. Look at section six in some of the PIMs; it's called Engine Dress.

Think about it; the engine had to be sealed up so the paint (and other) processes would not contaminate the inside. The only exception was the carburetor, for obvious reasons.

For a long time people thought that aluminum intakes were not on the engine when painted, but they were.

 

And most people still think that the coolant outlet and lifting hook that go on aluminum manifolds were painted separately.

They were not painted. They were installed, covered, and protected from paint by the manifold mask. As such they may have a trace of paint on them from mist that got under the mask.