My 66 has a 347 and the Spal setup with the two fans and shroud.  Started with a big block radiator and in about 2 years it developed a pinhole leak. I put in a Champion 24 inch 4 row that lasted about 15 years. The four row never overheated, but I am in California on the coast.
About 3 years ago, when the four row developed a leak, I put in a 24 inch Champion three row. In stop and go traffic for 45 minutes in Los Angeles at 105 degrees, the car did get hot, but did not overheat. I use the stock temperature gauge, so I cannot provide an actual temperature. Note that I do not have a stone guard on my car. I don't think it would make any difference, but I haven't tested that theory.

This is the one I just purchased for my 65 convertible.  I have the same one in my 69, using 69 shroud and five blade 17” fan.  They sell it with lower hose on either side. It clamps in place using a 67 top bracket and “make your own “ lower brackets or the original 67 lower brackets.  No ugly square top tank

Thank you all. I appreciate this. boss347convertible appears the 4 core did cool better for you, compared.

Rudi wrote:

That’s a nice looking rad and great price as well. I paid about 70 bucks more ages ago. At the time I couldn’t find any formed tanks unless you bought the Griffin or other big buck rads.
Mine is a three row, I wonder performance wise difference the two row is
Did I mention how much I hate the square top tank.🤬

I researched this years ago and row count alone can be deceptive.  Cooling is done by surface area and effective air circulation.  If a radiator can do that with 2 rows its fine, if it can't do it with 4 its not.  4 row radiators for example were huge years ago, but the companies I talked to said the issue you had was that the first three rows basically got all the airflow, and the radiating heat from the rows in front of that 4th row acted like a thermal curtain to prevent heat exchange.  Most aluminum radiators I've seen are two row, but they use larger tubes, so the tube surface area is likely the same or greater than a 3 row with smaller tubes.  Fin design is another key factor.  When companies are selling something they tend to extol its "virtues" and give only the information which makes their product seem like the best.  Point being, I wouldn't assume a 3 row is better than a 2 row.  First hand experience from someone you trust is always the best way to make an informed decision IMO. 
 

The Griffin in my 66 (same basic design as the one pictured) has two rows but is 1/2" thicker core than the one in the picture.  And about $650 difference in price...

Bolted to Floor wrote:

Overall thickness was a concern too. The extra row could be eating needed space for fans. I’ve heard lots of good things about Spal and the Contour set up.

FYI - The radiator I used (see above post), and the Spal electric fan I installed, left about 3/8" space from the nose of the water pump to the fan.