1948 2WD Engine Color

I am doing a frame off restoration of a 1484 2WD pickup that has been in the family since about 1954. It's going fairly well - some parts are taking a bit of scrounging to find, but nothing so far that money can't fix.

The original paint was Luzon Red (as far as we can tell from a few hidden spots that haven't faded too much). But - we are at a point that we have to answer a question that most guys cannot appreciate. I'm using an F-head engine - not original, but I've got it and I'll use it.

Does anyone know what color was used on the original engine (block and valve cover)? The machine shop is ready to paint the block and valve cover and what should we tell them to use? Just about every picture I've Googled shows the basic engine color as dirt or rusty.....