As far as the 2 vs 4 debate, I like to look at core thickness. Most 2 row are 1.5 . This 4row is 2.75 thick. That has to be more coolant flow and more heat transfer?
Lets get this out of the way. The radiator hasn't a thing to do with flow. Nothing. Nada. Zilch. Well......unless it's stopped up. lol
FLOW comes from the water pump and the flow size of the thermostat. Period. In fact, the more rows a radiator has, the more of a restriction it becomes. This is why a WELL DESIGNED two row radiator with either 1.25" or 1.50" tubes will outflow and out cool most three and four row radiators. That's why everybody's goin to um. They work!
My example I spoke of above is somewhat similar to yours, although my car has a slant six. I measured 10.2:1 when I assembled it, but I think I goofed somewhere because even with a large flat tappet (250 duration @.050") it STILL has over 175 PSI cranking pressure. It HAD a detonation issue when I first got it running. I did several thing one step at a time. Colder plugs, blocked off the exhaust to intake heat, tightened up the valve lash. EACH thing I did helped a little but didn't cure it. The one thing that did was when I put in the 160 high flow thermostat. I don't even have a temperature gauge....well.....it has the factory gauge and it works. It was running right at and a tick past half way before the change. Now it runs 1/4 of the way at the very most. Still has the slant six four blade useless fan. I think I could throw it in the ditch and it still wouldn't run hot at this point. That's what mine needed. FLOW. Once I gave it that, no more spark knock and it runs MUCH cooler and better. He's not pullin your leg. If you don't have a high flow thermostat, get one. A 160. I bet it might work.
