[Stefano]

I can't vouch for it being original to the car, but my L78 Manual has a correct three core Harrison "O" A "O" raised on the filler tank While the 4 core original Yenko radiator looks like "O" K "I" and they both say FILL ^ COLD and have an "R" on the Driver side tank Brace.

Of course both have "Harrison" Raised on the Filler tank.

I have seen one low milage original L78 4 speed 4.10 posi Camaro with a Curved neck COPO style 4 core radiator as well.