Bonus points for the bullet-proof looking engine cradle!
Self etching primer will work well on that small amount of surface rust. It looks like you got a bit more grease on the area above the PS pump. Probably had a distributor seal leaking above there, eh? Clean it well with simple green or fast 505 type cleaner and a scrub brush, then flush with water.
s***-can those ribbed belts. I'm sure you know that already.
There are some little 1/8 size holes that run diagonally between the cylinders. Be sure to clean those to help water flow.
I assume you're not going to drop the pan or the front timing cover? I think you should be okay with that.
My engine was abused to death, and I changed out a bunch of parts. Heck, I even put in a new (used) crankshaft.
When you mask off for painting, be sure to have your mask line well over onto the aluminum parts. Like 1/8" or so. They won't care if you hit them with paint, but if you miss some cast iron it will rust quickly.
Not sure what year, but it looks like you have a crank position sensor. Robbie told me to leave the o-rings in place, but slather the areas that need it with black FIPG. No leaks so far.
