COPO Chevelle radiator

[Ls6 Ragtop]

Not claiming to be a 69 expert but I'm with Jim on this one.
Every 69 I know of with HD cooling has a 3 row radiator.
The Radiator support and upper hold down plate were modified starting in 70 for those cars equipped with a HD cooling package to accept the IF coded inlet tank used on 4 row radiators.
For what it's worth the 69 L89 Chevelle I have here has a BO coded 3 row radiator and the COPO Chevelle that I have here has a BQ code 3 row.
These are both manual shift radiators and look identical but use a different resolution finned core.
BQ radiators were also used on some 454 Chevelles in 70.
Fwiw, Chris