The Aerodynamics of a Barn Door

Roger Johns’ 1947 farm truck does some serious haulin’

- Bob McClurg

THE ONLY HAULING ROGER JOHNS’ CHOPPED ’47 3100 SERIES CHEVROLET ½-TON DOES THESE DAYS IS THROUGH THE QUARTER-MILE, AND HE DOES IT TO THE TUNE OF 9.34-148. NAMED HOODLUM, THIS SLIME GREEN (IN THE OWNER’S WORDS) ’47 HAS THE AERODYNAMICS OF A BARN DOOR, BUT IT HURTS FEELINGS ON A REGULAR BASIS.

Built almost entirely by Johns’ company, RJ Motorsports, Hoodlum features a double-rail DOM round tube 115-inch wheelbase chassis. The rear suspension consists of an RJ Motorsports 4-link setup working in conjunction with a pair of Aldan QA1 double-adjustable #150 coil-over rear shocks. A 4.57:1 spool (with MW aluminum center section and REM polished MW gears) spins inside an MW 9-inch Ford housing and features MW gun-drilled 33-spline axles. The truck stops via a pair of four-piston Wilwood rear disc brakes. Up front you’ll find Art Morrison upper and lower tubular A-arm suspension deploying AM Mustang II front spindles, QA1 coilover front shocks, Wilwood four-piston front disc brakes, a 1 ½-inch AE anti-sway bar and AM Mustang-II-type rack-and-pinion steering gear. Wheels and tires consist of a set of black PlastiDipped 15x3.5-inch Weld Pro Star II front, and 15x12-inch Weld Pro Star II modular rear wheels rolling on Goodyear racing rubber.