stock SS radiator disappointing

[87octane]

While crawling all over the dead RWD SS at courtesy chev in San Jose, I inspected the radiator. I was disappointed to find it is a single core (probably 5/8" and not even 3/4"). I just finished a complete drivetrain swap in a customer's 97 Tahoe with towing package that had smoked 2 trannys and one motor due to overheat while towing a racecar on dual axle trailer, and it had a factory single core rad. What is chev thinking with underengineered cooling systems on vehicles with factory tow packages? I replaced the Tahoe 5.7 factory rad with an aftermarket dual 1" core all alum rad, better waterpump, and new stock thermistat, and the temp gauge won't budge anymore (of course).

I didn't have a tape to measure the SS core but I want to source a high end double core replacement immediately. Anybody else look into this yet?