1987 Chevy Corvette - Budget Brawler

Transplanted LS Power Turns A Milquetoast '87 Into A Bucks-Down C6 Fighter

Christopher R. Phillip Aug 26, 2010 0 Comment(s)
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Though a stock early LS1 is rated at an impressive 345 hp, Lovell suggested increasing its output to 425 hp with an AntiVenom Eliminator 2.5 cam. (The specs are confidential, but Lovell was willing to admit that it's based on a 115 LSA and gives the engine a sinister personality.) Other components utilized during the build include a ported LS6 oil pump, a VMAX Motorsports ported 90mm throttle body, an LS6 intake, and an LS7 timing chain. The cost of the build, including parts and labor: $1,100.

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"That was all I was willing to spend," Hardy says. "I asked Greg, 'How easy would it be for me to install the engine myself?' He said it would be easy, based upon my technical background, and if I needed any advice, he'd be happy to help."

Lovell's first suggestion was a set of Speed Hound Performance motor-mount plates specifically designed to transplant an LS-series engine into a C4 Corvette. They were a no-brainer for their $100 investment, and Lovell promised that they would make the L98-to-LS conversion go smoothly.

Though the LS1 fits within the C4 engine bay without any modification, Hardy notched two places on the firewall after test fitting-one on the driver side for header-bolt access and the other on the passenger-side firewall to allow extra clearance for the head.

Next, he installed a '90-'96 factory-style slanted radiator and shroud to accept a stock C5 air bridge, which he paired to an AntiVenom airbox. He then bolted on a set of Melrose LS-conversion long-tube headers (17/8-inch primaries), which he mated to the Vette's existing exhaust system (a parts mishmash comprising 3-inch stainless-steel pipes, an X-style crossover, Random Tech cats, and no mufflers).

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The wiring conversion was simple, too, thanks to an $800 custom-made harness from Current Performance Wiring in Port Richey, Florida. It allowed him to hard-wire the main and ignition power, the A/C and ECM signals, and the check-engine light, and to use GM-style plug-and-play connectors to power the LS1's myriad electronic connections (MAF, starter signal, O2 sensors, knock sensors, coil packs, et al).

Connecting the LS1 to the Vette's 700-R4 automatic transmission was the next task. Hardy says he found a super-simple solution: elongating the mounting holes on the Corvette's C-beam and sliding the trans forward about 1/4-inch. Then, he bolted a custom 3,600-stall lock-up torque converter to the 700-R4 bellhousing.

Hardy admits that he had a wee bit of stagefright before he inserted the key in the ignition for the first time. "I had never done an L98-to-LS1 conversion before and didn't know what to expect. When I hesitatingly turned the key, the new engine responded instantly and filled my ears with its tailpipe symphony," he says.

Six seconds later the performance ended when the LS1 mysteriously shut off. "I was ecstatic that the engine had roared to life, but completely baffled why it wouldn't stay running," Hardy says.

Lovell at AntiVenom had the answer. The GM ECM (a $90 eBay find) that Hardy installed featured a vehicle anti-theft system, or VATS, that had forced the engine into shut-down mode. "I went to his house with my laptop and turned off the anti-theft system. It hasn't given him any worries since," Lovell says.

Since the project's completion, Hardy has enjoyed his low-buck, LS-powered C4 as a weekend toy, all without the worries that plagued his old blown TPI setup. Of course, there are a lot of different ways to spend $5,000 on a C4. Was it worth it to put the funds into an LS swap?

"There's a huge difference between the new LS1 engine and the supercharged L98," Hardy says. "I keep asking myself why I didn't do the conversion much earlier. The LS engine gives me the peace of mind that I can turn the Corvette's ignition key at any time and never have any nagging concerns about what could go wrong.

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