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1981 Chevrolet Corvette - Beauty And Beast

This Big-Block '81 Wasn't Built To Be A Trailer Queen

Scott Ross Nov 29, 2010
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There's a lot to be said about ultra-high-dollar rides-cars whose owners have invested so much time and money into them that they're afraid to drive these otherwise roadworthy masterpieces.

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Except this story isn't about one of those. It's about a shark that was built by someone who was looking to do something else with his next project.

Several years back, Frank Cagle had a show-stopper in steel-a '67 Chevy II Nova Super Sport that he'd put a lot of time and effort into; it even bore Chip Foose's autograph. "It just went to shows, and finally I got tired of not being able to drive something," Cagle says from his Birmingham, Alabama home. "I said to myself, 'What do you want to drive that looks sporty and is not what everybody else has?' The C3s just stood out all by themselves."

That would be the oft-maligned '68-'82 Corvettes, rushed into production when the General was blown away by the Mako Shark II concept car back in 1965. This was the Corvette generation that suffered the most over the years because of uneven early build quality, tightening Federal emission and safety standards, and a perceived lack of what "a real Corvette" should have. (Of course, that didn't stop Vette buyers from snapping them up in increasing numbers during the mid-to-late '70s.)

Cagle set out to find a red-on-red shark for a project car, and the first one he found turned out to be a good one. Too good, in fact. "I found one in Cincinnati, flew up, bought it, and drove it back to Birmingham," Cagle says. "On the way back, I got to looking at the car, and everything on it worked-the seat-belt buzzer, light dimmer, even the clock was working. I said, 'I can't destroy this car-it's in too-good shape!'" When he got home, Cagle put that car up for sale and started his search over.

On eBay, he found an interesting C3 at a shop in St. Petersburg, Florida. It had the red exterior/interior he was looking for plus a new interior, lots of new chassis and trim parts, but no engine or transmission. A call to the shop revealed that this particular '81 had been brought in for a high-end paintjob, with all the glass, interior, and trim removed, but the owner never came back to pick it up. It sat there for three years before the shop owner got a mechanic's lien on it, and the State of Florida granted him a clear title to the car. It wasn't all together, but it was altogether what Cagle was looking for, so the deal was done. "I loaded up my trailer and made the trip down to St. Pete, loaded it up, brought it back to my shop, and started working on it," says Cagle.

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For an engine, Cagle not only had a big-block in mind, he had one in his shop. Actually, when he brought the '81 home, he had two Chevy big-blocks-a 468-inch one and a 540-incher built by Jon Barrett Hot Rod Engines in McLoud, Oklahoma. "I originally bought the Jon Barrett big-block to go into a '67 Nova Pro Street that I was making," says Cagle. "Another guy bought the Pro Street project from me, and I'd had the 468 built up for the Corvette, so now I wound up with two engines. I said, 'What the heck-I'm going to put the Jon Barrett big-block into the Corvette, and I'll give the 468 to my son, who'd just finished up a '72 Camaro split-bumper."

But the Barrett engine had some clearance problems, thanks to its tall valve covers topping a set of equally tall roller rockers, along with changes Chevrolet made to the C3's engine bay after the last factory 454 was installed in '74. "I had to take a 4-inch notch out of the firewall just to get the valve covers to clear," Cagle says. "When you start dry-fitting all that stuff, you find [these things] out." He also found out that there was a clearance problem with the Zoops pulleys up front. "The only three-pulley crankshaft pulley they make for a big-block has this large overdrive unit on the front, which means you have to cut a 2-inch notch out of the crossmember to get it to fit."

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Next came a transmission-a 700R4 overdrive automatic, built for high power by Monster Transmissions & Performance in Spring Hill, Florida. Farther aft is another powertrain item that's up to the 540's 635 lb-ft of torque: a 12-bolt rearend inside a four-link suspension setup. Cagle says the OEM rearend housing wasn't up to the job, not with this engine replacing the original 190-horse L81 350. After some more online research, he found RaceFab's website, which led him to the shop that made a custom four-link suspension system that replaced the IRS (and its tendency to squat under hard acceleration). Inside the 12-bolt's housing are Moser axles and a 3.73-geared Auburn posi differential.

As with any build that isn't a straight remove-and-replace job, some other problems cropped up, which Cagle solved. One had to do with the wiring, and how to connect a set of AutoMeter Phantom gauges to it. "As you know, the Corvette electrical system has all those ribbon cables with plug-in connectors," he says. "To put regular gauges in it, you have to cut the plug-wiring harnesses all off, then chase everything down-from turn signals to high-beams to everything you're gonna do-and then rewire the whole car, basically." Cagle also installed NASCAR-style switch gear for the electrics.

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For the exhaust system, Cagle wanted to run a set of side pipes, but ones that didn't look like the'69 Stingray's factory RPO N14 side-mounts-and he wanted them to match the "blackout" chrome trim he put on the body. He chose Hooker's 4-inch-diameter "Show Tubes," which needed some fabricating help to connect with the McJack's headers and their 21/2-inch collectors. "We had to do some sizing down, and I had to use an exhaust elbow from a tractor-trailer to make that turn up under that car." The exhaust system also has a set of Pypes electric cut-outs, controlled by a switch on the console where the emergency brake handle used to be.

Once complete, Cagle had a C3 that was ready to run. What's it like to drive? "Believe it or not, it drives absolutely marvelous," he says. "When you get out on the road, it's an absolute dream. I'm only running about 1,800-1,900 rpm at 75 [mph], and with the four-link keeping the rear tires straight and the Steeroids rack in the front, it drives like a dream. And it's extremely quick!"

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For too many people, the factory-equipped C3s from '72 onward weren't as quick as their midyear and early-shark predecessors. Cagle says that those much-maligned third-gens are worth a look as a project car. "Right now, the C3s are the next group of cars that people are going to be able to go out and purchase at a pretty good price, build back to a nice driver car, and still be able to make some money on it, and not get upside-down," he says. "Maybe not a numbers-matching restoration, but if you want to make a nice restomod out of a C3, that is the best-looking Corvette body style ever made."

Spec Sheet: '81 Coupe
Owner: Frank Cagle; Birmingham, AL
Block: GM Performance Parts Gen IV big-block, cast iron
Displacement: 540 ci
Compression Ratio: 9.5:1
Heads: All Pro aluminum
Valves: 2.19/1.88
Camshaft: Comp 11-246-3 (0.552/0.555-in lift, 230/236-deg duration, 110-deg LSA)
Rocker Arms: 1.7-ratio
Pistons: Probe forged aluminum
Crankshaft: RPM forged steel
Rods: RPM forged steel
Intake Manifold: Edelbrock Air Gap aluminum
Carburetor: Holley Street Avenger, 870-cfm
Fuel Pump: Holley
Ignition: MSD 6AL electronic
Exhaust System: McJack's custom headers, Performance Car Craft dual exhaust with electric cutouts and 4-in Hooker "Show Tubes" side pipes, Flowmaster mufflers on front-to-back pipes
Transmission: 700R4 automatic with Hurst Competition Plus shifter, built by Monster Transmission
Torque Converter: 3,600-rpm stall speed
Driveshaft: Custom
Front Suspension: Stock '81 Corvette
Rear Suspension: Custom RaceFab four-link with coilovers and QA1 shocks
Rearend: GM 12-bolt differential with Auburn Positraction differential, Moser axles, and Richmond Gear 3.73:1 gears
Brakes: Baer discs with slotted/cross-drilled rotors (front/rear)
Wheels: Centerline billet aluminum (17x8-in front, 18x10-in rear)
Front Tires: 17-in radials
Rear Tires: Mickey Thompson "street slicks"
Fuel Octane: Premium
Weight: Unknown
Best E.T./MPH: NA
Best 60-ft. Time: NA
Current Mileage: 278 since rebuild
Miles Driven Weekly: Approx. 50



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