Evergreen PA20500.50 97-04 Ford F150 E150 E250 Freestar Mercury 4.2L 256 OHV 2 Engine Piston Set (Oversize 0.50mm = 0.020") Fits: 97-04 Ford F150 E150 E250 Freestar Mercury 4.2L 256 OHV 2 (see description below) Ultra Performance Custom Made Premium Grade Aluminum Silicon Pistons Gas Nitrited Steel Rings, 50% Longer Life, Reduce Tension with Better Fuel Economy, Reduce Cylinder Wear Much improved design with more efficient oil passage holes in oil ring groove. Minimizes fractures & cracks. No more gummed up oil. Reduces engine failure Meets or exceeds OEM specifications. Easily lasts 150,000+ mile