John Sonnefeldt has been driving his 1971 Chevelle SS 350 for years. It was oringinally a blue car with a black interior and top, with black SS stripes and a set of wheels. However, John was tooling across the Mississippi river on a cross-country road trip with thousands of other hot rods… you know the one… when the 350 decided to take a dump. Bummer. Or… opportunity!
The end result was more than a facelift… this Chevelle has a 3-letter heart transplant... L-S-2.
Sonnefeldt works for Tratech, the company that makes the Detroit Locker Tru-Track differentials, and they were considering building a vehicle to showcase their parts at high-profile events. It just so happens that Sonnefeldt had a car he wanted to build. Sonnefeldt recognized the opportunity to team up with Tratech, and they came up with the car you see here.
The most obvious feature of the ’71 Chevelle SS is the black and yellow 2-tone paint scheme sprayed by The Custom Shop in Flanigan, IL. Sonnefeldt likes black cars, but he realized that this Chevelle is going to be driven a lot, so he elected to have the sides shot in a yellow pearl to keep the car looking clean after a hard day of driving. It’s hard to make a black car look good when it’s dusty or covered in tire rubber.
Which brings us to the most significant upgrade, the new GM Performance Parts LS2 crate motor.
The LS2 may sound familiar; it’s essentially the same as the LS2 found in 2006 Corvettes. It packs 400 cubes and horsepower from the factory, but Sonnefeldt kicked that up with a comp roller cam and a FAST intake manifold. Managing the system is a Fuel Air Spark Technology (F.A.S.T.) XFI stand-alone engine management system programmed to run this style of engine. As of this writing, Sonnefeldt didn’t have chassis dyno numbers yet, but he’s claiming 400 big ones at the rear wheels, yet the car still knocks down 17-18 mpg thanks to the EFI and the overdrive.
One challenge of adaping the LS2 to a 30 something musclecar is the throttle… the LS2 uses a drive-by-wire system from the factory, and that’s a bit tricky to retrofit at this point. Sonnefeldt solved that one by using an LS1 style cable throttle, and the engine is none the wiser thanks to the F.A.S.T. ECM not telling it any different.
An MSD APS alternator keeps all the electroincs fed with its high-amperage output. Mounting these is easy thanks to an innovative mounting system that allows you to clock the alternator in vertually any position.
Sonnefeldt installed a TCI Street Fighter 4L60E 4-speed automatic overdrive tranny behind the engine, but he was able to “keep it fun” through the use of Twist Machine’s Shrifter. The Shrifter is an aftermarket paddle-shifter and controller that mounts behind the steering wheel allowing for Formula One style shifts without removing your hands from the wheel.
Flip the one paddle and you upshift, flip the other and the transmission downshifts. It’s a lot of fun, and it works with most electronically controlled transmissions. Sonnefeldt used a TCI controller for his installation.
Other interior tricks include carbon fiber accents in the cabin, and real leather seat covers in the original SS seat pattern from The Paddock. Newer style 3-point seatbelt harnesses keep the occupants safe, air conditioning from Hot Rod Air keeps them cool, and a gaint MTX audio system keeps their ears ringing. Sonnefeldt cleanly connected the Hot Rod Air system to the original Chevy A/C controller using microswitches to detect the position of the selector levers. It’s a cool way to do it.
Under the car, Sonnefeldt slipped in a complete Hotchkis coil-over suspension system, complete with tubular control arms and sway bars. A set of adjustable QA1 shocks keep the bounce under control. Out back, a Moser 12-bolt lives under the Chevelle stuffed with 4.10:1 gears and a Tru-Track limited slip differential, of course. Another interesting approach is the dual Bassani exhaust pipes exiting through the rear valance… it’s kind of like a Chevy version of the Buick N-25 cutouts in the rear bumper. Clean.
Now the car cruises in style with the LS2 humming and Sonnefeldt slapping gears on the Shrifter. You can see this car in person all over the country at many of the motorsport events Detroit Locker sponsors. It will be easy to spot; you’ll hear the crowd talking about “the black and yellow Chevelle with the LS2 in it!”
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