Hot Rods Color to paint engines?

I've noticed through the years that many A/B guys paint their motor, or sometimes just the head, Red-
Was this a thing... is it still?
When I ordered my head I just painted it Model A Green, but I've never seen others like that. Just wonderin'...

 

Red motor = 10 added HP minimum, increases with number of cylinders.

 

And don't forget chrome.

 

I paint all my flathead v8 engines flat black. I think it contrasts well with the aluminum heads and intake and doesn’t show oil leaks and road grime like bright colors do.

 

Black, preferred! Dumps the heat I use gloss on the block & heads.

 

Some paint the block red and the head black. HRP

 

I need a bucket of red paint !!

 

Lol- that would be an idea for whoever has Joe Gemsa's old yellow T-bucket w/ OHC head. He Chromed the rear axle housing on it.