I adapted a stock truck radiator into my '52 3/4 ton. I fabricated my own sheetmetal fan shroud around it, and it never runs hot, not even sitting in traffic for extended periods of time. I was running a 350, but that wore out and now I have a 283 in it.
If you can get the aftermarket radiator that fits in the stock location, that would be best. But it is expensive, around $600 bucks I think. Maybe in your case, ADpartsman, an electric pusher fan on a switch inside the cab might help keep its cool when you're stuck in traffic.
