65 GTO radiator
 

I have been looking for a original Harrison 4 core radiator or tanks for my 65 GTO non A/C manual trans. for a while. I heard a story about someone who had there 3 core recored and in place of the normal 1/2" cores they used 3 rows of 5/8" and ran a extra row or two so it cooled like a 4 core. Anyone ever heard of this and where?

Radiator
 

Not sure if this is of any help to you. I had my original four core non AC Harrison rad re cored a few years back for my 65 GTO restore project. I was told that the rad technology has changed greatly since these rads were first made. New style cooling tubes are now dimpled to slow down coolant flow to allow more efficient heat transfer. This greatly helps especially in the early vertical flow rads vs the later cross flow style. Coincidentally when I was dropping off my rad, another customer brought in his original equipment 3 core non AC manual trans Harrison rad for his 65, for re coring. I have since run into the other customer and to my knowledge has no cooling issues. In my neck of the woods this makes two original GTO non AC cars that were/are equipped with 3 core rads. I have not had any cooling issues with my newly rebuilt 389 tripower. No extra work done to the cooling system other than OEM set up; clutch bent tip fan, shroud, and made sure that the divider plates in water pump were properly adjusted. I was fortunate in that I have a large truck rad shop in my area. I am assuming that you have a three core rad. If it were me I would locate a reputable truck rad repair shop and get their opinion.

John, check this thread.... http://forums.maxperformanceinc.com/...72#post5308972
It was the best move I could have made.