While not exactly correct, I painted the block/head etc in Middle Bronze Green, but left the aluminium parts silver. Also painted the starter and dynamo in parts simply because I like how they look...

Regarding how to paint: clean, dry cast iron takes paint really well, and won't rust as readily as steel does, which also helps paint stay on.

There are surely techniques which can help, but once the engine is installed and all of the attached parts are in the way, you can't see most of it anyway, so painting the engine block isn't anywhere as difficult/specific as painting, say, the body panels.

Is this by far the best approach to paint the engine? I've heard a lot of different ways including use of POR15 and applying high temp paint while it's still "tacky". How many coats?

Yes, my original SPI engine was red (although hard to see under all the grime).

Red?
I didn't think that was used at the factory.

Green, black, yellow(gold), ......

Yes, I think early engines were a shade of green, later engines red. I went to the paint store and used their chips to come up with something close.

But I also painted before assembly. Make sure you use a polyurethane acrylic with hardener so it will be resistant to gasoline, oil, etc.

This was my paint formulation

That's awesome! I watched this before and didn't think of it. Thanks!

the painted engine is shown at about 9 min in.

https://www.youtube.com/watch?v=hbZFjIofMhw

I do believe that the early cars were Medium Bronze Green , from rocker cover to gearbox….including clutch cover and generator

• I just finished putting my engine and gearbox back together and now time for prep and paint. I've seen some A series engine carrying BMC/ MOWOG green from rocker cover to gearbox casing and some would just have the head and block green and then silver or grey for flywheel housing and gearbox. Which is correct??
• I like it looking old school that's why I wanna know. Thank you.