Radiator Cooling

Hi all, Another daily question. I've heard that most old cars have overheating problems when hill climbing, etc., specially in the summer. When I was a kid, one of the family early cars overheated every time we went to the Angeles Crest National Forest in the mountains North of Los Angeles. I'm wondering if the issue was the poor air flow through the radiator since it did not have a shroud to force air through the coil. Since my 28 car is all apart, now is the right time to correct another faulty design problem.

And an associated question is about my lack of a radiator overflow or expansion tank. There should be one, right? Yes, I know its an ambient pressure system, but the expansion liquid should pull back into the radiator if I configure it right.