Perfect, thanks. That's how I remember the 4 row rads too but it's been a while.
I could be wrong but I think by 69 the 4 row cap might have been in the middle.
Howmac may chime in here with his 69 L72 experience and help out.
I am using a 4 core rad with clutch fan (7 blade) for my 69 Biscayne ( attached picture ) and have another for my SS project. I have zero issues on the hottest days . I have parted out a few Canadian 427/335 hp B bodies, and those all had 2 core rads with the 4 blade from factory ( both non A/C )
