These new, redesigned Mustang Heater Cores now fit just like the originals-they are just made of aluminum rather than the original copper/brass style.
Keep in mind that there are several brands on the market. This one is made for this specific fit and will fit correctly.
For use with 65-66 Mustangs (Air Conditioning or No Air Conditioning) and 67-68 Mustangs not equipped with factory Air Conditioning.