Wilwood has worked with Jim Marsden from Gigglepin Racing for years on their off-road program. They recently debuted their new Ultra4 4400 Miller Motorsports Pro Chassis race car, dubbed "Mistress", and talked about the hard parts, and the reason for some of his choices in building it. The biggest departure from conventional wisdom, is the use of a Spidertrax Off-Road solid front axle instead of independent front suspension.


Powering the car is an LS7 440 cubic inch V8 motor with 650hp on pump gas, built by CBM Motorsports in California. That's connected to an electronically controlled GM 4L80E four speed automatic, with sequential shifting capabilities hooked to a bullet proof Atlas 2-speed transfer case. Axles are the new Spidertrax pro series with 4.5-inch tubes, front and rear, with the latest advances in steering knuckle and universal joint design, plus stronger 45 spline outers. FK Rod Ends hold them, and Tubeworks Race Line supplies the high pinion CrossTie differential.

Obviously, the car features a Gigglepin Winch, with a GP100 front and center. Laser High Performance Lighting is all over the front as well, turning night into day at the flick of a switch. The lights, the electronic dash, and everything else, get a charge out of Odyssey Batteries, which Jim describes as "...Those little boxes of magic, they sit down under the floor, and power the whole thing."

Our favorite part, obviously, are the Wilwood Aerolite six piston brakes, front and rear, which Jim prefers to use with EBC Blue pads (you can get pads for Wilwood calipers in all the top pad compounds from multiple brands). Putting the power and braking to the ground are Maxxis Trepador tires on Raceline Wheels. Keeping those tires stuck to the ground are Fox shocks, 3.5-inch five bypass shocks in back, with 2.5-inch four bypass units in front, with 2-inch coil overs holding it up.


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