Top End Mods: Valvesprings, Pushrods, and Head StudsAdding to our 2008 Ford F-250's bulletproofed 6.4L bottom end (assembled in “International Threat Part 2,”), we’re finishing up the Ford Power Stroke’s long-block modifications this month. Much like we did with the rotating assembly, we’re addressing weak points with aftermarket replacements yet retaining factory components that have proven durable in high-horsepower applications. In an effort to stand up to big boost, high cylinder pressure, and 4,000 rpm, our top-end parts list consists of stiffer valvesprings, stronger pushrods, and head studs. The heads, head gaskets, lifters, and rocker arms (albeit cryogenically treated) are genuine Navistar International components.

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Photo Gallery: 2008 Ford F-250 International Threat: Part 3 - Diesel Power Magazine



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