Picking out a replacement radiator for your GTO can be a little confusing sometimes. That’s why we’ve made it simple for you and put together this simple tech guide.

"Factory" AC vs non AC is the first question most people should consider. 64-67 Tempest, LeMans and GTO's had either an AC radiator support or a non AC support. The AC radiator support is 2" taller and can be identified easily (see pictures). The only exception to this would be in 1964, GTO's all got 17.5”.  The easiest way to find out what you will need is to measure your original radiator. If you have a 15.5” core, then you will need the non AC radiator regardless of whether you are installing aftermarket ac. If you have a 17.5" core, you'll need an AC radiator regardless of whether the car still has AC or not.  

It is very common for Pontiac owners to swap out original motors for newer Pontiac motors like the 400, 428 or 455. Here are some basics to consider. Originally, all 64-67 A-body Pontiac radiators were downflow (meaning tanks on top and bottom). The 1964 and 1965 models have inlet/outlet both on the passenger side. The 66-67 models have the inlet moved to the driver side while the bottom outlet stayed on passenger side. Pontiac engineers realized this was a more efficient design.

All filler necks for 1964-67 A-body Pontiacs were in the same spot except for 1965 non AC Tripower cars where the filler moved 4" to accommodate a different fan guard.  

From the factory,  most non AC cars had 3 row radiators and a 5 blade fan. The Tripower and heavy duty cooling option non ac cars got 15.5" 4 row radiators with a 7 blade fan and clutch.  All AC cars got 17.5" radiators, 7 blade fan and clutch regardless of options.     All of these components are available in the aftermarket.  

Fan shrouds:
1964 cars did not use a fan shroud.
1965 AC cars had a metal fan shroud.
1966-67 AC cars had a plastic fan shroud that was essentially the same as the metal shroud.
Pontiac also introduced a dealer installed shroud option for the non AC cars because of numerous owner complaints about running hot.

All Cold Case radiators will allow for the reinstallation of these OEM fan shrouds.

Cold Case upgrade notes:

• When upgrading from a 3 row radiator to a 4 row radiator or a Cold Case radiator, an installation kit (RPE58) is necessary since the lower brackets and insulators were smaller on original 3 row radiators.    
• Cold Case offers SD/HO radiators for severe duty applications. While they are a little less original looking, these models include dual 1 1/4" tubes for maximum cooling.   They are normally sold as kits with electric fans and electronics.       

Be on the lookout over the next 6 months for Cold Case's new Radiator Support conversion kit which would allow you to use a 17.5" radiator in a non AC car!