Replacing the radiator in a big block 76 cutlass. It's a .030 over 455 with 11:1 forged TRW pistons. Actual comp.ratio is about 9.5:1. 280/290 duration .472/.496 cam and headers. It has a 3 row brass radiator in it that I had repaired but is leaking again. Wouldn't stay cool on a hot day or if I was running it hard.It's coming out. Don't know whether to try an aluminum 3 row or go big with 4 row. The big one is only like $100 more so I'm thinking go with that but a hundred bucks will fit in my pocket real fine if it's just overkill. what say you all?

 

I'm not a fan of aluminum radiators and I've never seen a 3 row model? Go with the 4 row brass.

 

I disagree. A high efficiency 3 row rad will out cool a 4 row.

 

The bottom line is try to get the unit which transfers the most heat. The thermal conductivity of copper is better than aluminum, but when it gets combined with zinc to make brass, the aluminum transfers better. But there are other factors that determine the total ability of the unit to transfer heat. I have a tendency to go for the thickest core that will fit, irrespective of the number of tubes. I don't like plastic tanks. If a repair is ever needed, the brass & copper may have an edge in ease.

 

Actually a good design rad like a Griffin 2 core will out cool a 3 or 4 core. Get the Griffin Dominator series for the A body. My current 2 core out cooled my Champion 3 core in my Cutlass. The Olds 403 and 455 run warmer than some other brands. Make sure you have a factory 7 blade fan with a heavy duty clutch or good electric fans and a heavy duty closed impellar water pump.

 

http://www.usradiator.com/cores

You decide.

http://www.cgj.com/2013/06/27/alumin...-great-debate/

5 part debate.

 

A new radiator with clear tubes of any materials or design will likely outperform a used radiator with partially obstructed tubes of any materials or design.
I wish that there was a side by side comparison of new radiators made of different materials and designs which indicated actual heat transferred to the air. Then we might get an accurate evaluation.
You can use your infrared thermometer to search the core for non-uniformity or cooler areas on operating used radiators.
On coolant try to get one that is less acidic. The acid seems to be most hard on aluminum.