Engine Compartment

I won't disagree. I would also strip down to bare metal, prep any pitted areas with some sort of a good rust fix product, epoxy, filler, lots of sanding, high build primer, more sanding, then base/clear. However, my plan, as outlined in post # 8, is anything but a 'quickie' paint job. Notice that I said, "This is how I would recommend you doing it at your experience level.'" It sounds like you know what you are experienced, but the Op is not. If he did what I recommended, it would probably take him several days, and he should come out with a paint job that will look good and last several years. runs in primer can be sanded, but if he can spray the paint without runs, it should look great. The rattle can primer @RustyRatRod and I recommended is actually a very good product.
BTW, @nodemon, feel free to contact me by PM if you have any questions.
It's true I do have many years of experience but I didn't always. If your doing bodywork and paint or building a motor learning it the correct way, to do it the best you can is something that you should strive for. In this case R and Ring the motor twice sucks along with paint work that doesn't last. Take the time and do it correctly.