Technical Cleaning Heads after Porting for Painting

I just finished the port work on some heads.
Everything I’ve seen says to wash them with soap and water then dry and oil.

but I need to paint them.
So
Do I try to wash them then paint before oiling and hope they don’t flash rust?
or
Do I pint them now and then wash after the pint has dried?

 

Yes.

Instructions for how to do engine assembly work generally don't include cosmetics. So...like you figured out, you need to modify the instructions. I usually paint heads after assembly, along with the block, oil pan, etc. But if you want to paint them before putting them on the engine, then do so. Do the paint prep cleaning, paint them, let dry, wash with soapy water, and oil the "inside" parts if you feel you need to. I don't bother putting oil anywhere except the valve stems/guides, but then, I live in AZ and bare iron things don't turn brown instantly here.

 

Lots of compressed air and a brush, followed by a can of brake clean and a rag

 

Follow up,
I washed the heads with thinners and a paint brush then painted them,

the paint can cure for a few days then I’ll wash with soap and water, dry, oil then assemble

 

I wash them in soapy water, then dry with compressed air and a heat gun in the water passage. They lightly flash rust, but nothing a good can of primer can't handle.

 

I use kerosene first, apply with a brush to get into the grain of the cast iron then after its dry, brake cleaner.