For the 1967* - 1969 FE / Big Block Cougar and Mustang and 1970 351c & 351W with AC and or heavy duty cooling package.
For optimum cooling you will want to purchase a shroud as well. Most Cougars these days have been bored .030 or more and many have had performance upgrades which all lead to increased heat.
Upper port 1-1/2"
Lower port 1-3/4"
Before you buy fancy wheels, valve covers or most anything else (except brakes) this should be at the top on your list.
Many applications only call for a 2 core but we feel more is better especially when the price is the same.
* Note: This radiator is not correct for the 1967 390 or 428, as those came stock with a 23 1/4" radiator but this radiator will work fine if you use the 68-70 lower cradle mounts.
Check out this video