We run a 70 challenger with a 512 ci big block. It is an dedicated autocross car. It is driven on the street as well. It spends a lot of time idling in line before runs and also sometimes multiple back to back runs. The car previously had a Champion radiator with 2 speed electric fan and custom shroud, it worked pretty good but on hot days it would creep up after back to back runs but was barrable. It started leaking around the tubes earlier this year(been in the car for several years). So I started searching, was gonna go with GRIFFIN but wasn't readily available. Ended up with a COLD-CASE radiator. They say their oversize 2 row will out perform 3-4 rows. THEY ARE CORRECT. Very noticeable temp decrease at least 15-20 degrees on very hot day idling. Actually one very hot day we were laughing about how much it DECREASED the engine temp (compared to Champion)and could be controlled at 200-205 degrees. Don't even worry about it anymore.