I would of used some bodyfill, in the deep pits. It would have helped with the look of it. I know that there just engine pieces, and noone is going to see them, but its good practice.
You did good with sand blasting them, but body, then sand, primer, sand some more, and then paint and clear. If you do that, they should look pretty good.
Did you use spray cans or a gun? With the smaller pieces, you could get away with a spray can, but if doing the whole car, use a gun. Using a gun is hard if your just pick it up, it takes practice. Leave a good weekend for a whole car. Not to mention, you need a well ventilated area to paint in. Just adding my know how in this area in. Hope it helps if you need to do more.