Shoot, 13K mile castings? I'd use them. Stock they're good to 400hp or a little more.

The 2.02 valves won't help but they won't hurt you except below 3000rpm. No use to switch to different heads just to get a little smaller valve, IMHO.

Fast68 outlined it for you. Smooth out the bowls, there are usually discontinuities under the seat. Make sure the short side radius is smooth and I think Fast was saying make it a more gradual transition from horizontal to vertical.

I think the pushrod pinch is large enough to not restrict flow for a 318. I'd leave it. I'd think you don't want to make the port very much bigger.

R.