it is my belief that the four core radiators didn't come till later in the second gen run - I believe all the rads for the early cars were two or three core units.
I believe that the rads can be re-cored into a four core rad - but original units should in fact be three core.
Here's the cars I know best (because I cannot base my assumptions on cars I don't know a history on):
1) my 1970 Formula; original three core rad is still with the car.
2) my brother's 1973 Formula (350/350); original two core rad was recently swapped for a 1980(?) four core rad.
3) my cousin's 1971 Trans Am (TH400/AC); to the best of my recollection it has a three core rad (I'm going from memory) - the car is painfully original - I can confirm and post later what it has
if the forum will let me reply again here later.
