A 3.91 at the eighth-mile stripe on a drag radial that looks almost too small for the job isn’t something a stock small-block Mustang was ever meant to produce, but that’s exactly what Josh Klugger’s Fox Body delivered in qualifying. Behind that number sits a 526 cubic inch stroker short block, twin 102mm turbochargers, and a FuelTech FT500 engine management system working together to survive cylinder pressures the factory 302 was never designed for. Read on to find out what it actually takes to build a small block that can run numbers like that.