GT40 heads

Ok you really need to specify exactly what you are looking for.

best? the only way you can get gt40 heads are on a 93 cobra and an early 96 explorer. the gt40p's are a different type of head that need special exhaust headers.
 
The 96 Explorer's had the std GT40 heads(like the 93 Cobra 5.0). At some point in 1997, the switch to the GT40P heads was made. These are the ones with the revised spark plug locations and header fitment issues. They also have the same smaller exhaust valves that the std small block Ford heads had (1.45-1.48)