GT40P Cylinder Head

The Ford Racing F77E-AA represents the GT40P casting, a significant upgrade over stock E7 cylinder heads for Ford 5.0L Windsor small-block engines. This head was originally found in mid-1997 and later Explorer and Mountaineer SUV models, carrying the part number F77E-AA. It is designed for 1997-2001 model years and offers a 9.5:1 compression ratio when installed on a stock engine setup. Compared to the restrictive factory E7TE heads, the GT40P offers improved airflow and a foundation for enhanced performance. These heads are known for their potential to unlock more horsepower and responsiveness from the 5.0L V8. It is important to note that the stock valve springs included with GT40P heads are generally considered inadequate for even a stock 5.0L HO cam. Replacement with an appropriate aftermarket spring package is imperative to ensure proper valve operation and prevent potential damage. The choice of springs should be matched to the specific camshaft and rocker arm combination being used.