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Boosted on a Budget: The Chevy C20 With More Bang Than Buck

For many car enthusiasts looking to make more power in a reliable and efficient manner, the LS swap is the way to go. A small-package, powerful V8 with endless tuning possibilities and an abundance of aftermarket support, the LS swap has become the sensible option for many. However, building a high-powered engine with forced induction seems to be out of the budget for most garage mechanics looking for more power, but Justin Shears set out to build a classic Chevy truck that defies all that we know about the cost of horsepower.

Shear Performance C20

As the owner of Shear Performance, a hot rod builder and general automotive repair shop in Costa Mesa, California, Justin has built high-horsepower cars and trucks, including LS-swaps, on many of his customer's vehicles. But when it came down to building a truck for himself, he wanted to put together something that could reliably make decent power while staying on the budget-friendly end of the spectrum. His project began as a humble 1971 Chevy C20 pickup truck, sporting a patina orange paint job. Justin's plan was to keep the truck unassuming, in a true sleeper format of silent-but-deadly performance.

Justin's C20

Budget Power

The LS-based V8 swap was an easy choice for Justin. With so many documented classic Chevy builds sporting LS engines, and plenty of aftermarket support, this powerplant made the most sense. Opting for an easy and cheap find, Justin began the engine build with a stock junkyard 4.8L long block from a 2004 Chevy truck. Although not a true LS due to a cast-iron block instead of aluminum, many of these truck engines can be found for under $1000 in running condition with relatively low miles.

4.8L GM LS Based engine Shear Performance

With an turbocharger on the mind, Justin began assembling the powerplant with boost-friendly parts to keep the compression ratio low and the revs high. He swapped in a cam from an LS9 engine and added a set of Bosch 210 injectors to support the fueling needed for boost. Even when it came to the turbocharger, Justin opted for cheap, but effective. After a careful eBay search, Justin had a 76mm T4 turbocharger in his hands, and began building the exhaust manifold and plumbing needed to run it. An Innovate electronic boost controller and wideband air/fuel gauge was added to tune the truck efficiently.

76mm turbocharger  

With the engine assembled and wired, Justin moved to find a transmission that would fit his needs. The stock GM 4L60E that comes behind the 4.8L wasn't stout enough to handle the extra force-fed power, so Justin found a Craigslist ad that seemed more promising. The ad was for a used stock GM 4L80E transmission normally found behind a 6.0L truck motor, but this transmission was previously mated to a 6.0L LS in a Ford F100, and behind another 6.0L LS in a BMW 7-series before that, all with an unknown torque converter that Justin scored for free in the deal. Needless to say, he came home with this gearbox and promptly mated it to the 4.8L.

Chevy C20 Shear Performance

Stock Support

Even in stock form, the rest of the Chevy C20's drivetrain could handle the power Justin was shooting for. The factory Dana 60 rear axle was outfitted with a 4.10 ratio ring and pinion, complete with a posi-traction differential. Justin's C20 is rolling on a set of 265/75/16 Nitto Terra Grapplers for a smooth, quiet-ride on the highway, while retaining the classic farm-truck look with white steel wheels. Although Justin doesn't have plans to take the C20 off-roading anytime soon, he knows that when the day comes, the Terra Grapplers will be ready to grip.

Terra Grapplers on the Shear Performance C20

Other Modifications

A few other modifications Justin made to the C20 include a Walbro 450 fuel pump in a surge tank fed by the stock fuel tank, 4-inch turbo-back exhaust with a Gibson muffler, and a refresh of the factory AC, power steering, and power brakes. The factory gauge cluster was converted to full electronic function, including a 120 mph speedometer and 7,000 rpm tachometer with 6,500 rpm redline. Shear Performance makes their own cruise control module, so Justin installed one to make the long drives easy. The interior was also treated with orange and black houndstooth upholstery to match the orange exterior paint.

Chevy C20 interior Shear Performance

Justin's modern-modded C20 is a prime example of a build that is both fun to drive and attainable with most budgets. More so, it's one of the easiest ways to have a truck with classic looks, but daily driver comforts and performance. Even with a junkyard engine and eBay turbo, it oozes cool at the seams, and is a big attraction at the shows it attends, even before you peek under the hood. Justin has more plans with this C20, including a forged 6.0L block that is currently being built. With a larger displacement engine, we're guessing more boost is also on the way. Whatever Justin has in store to make more power in this old Chevy, you can bet we'll be around to give you a horsepower update. 

Shear Performance C20 interior

Like this cool old truck? We've also profiled a 1952 Ford F100!

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