t’s been said that legends rarely live up to their hype, but the original, all-aluminum ZL1 big-block did just that.

Originally conceived as a lightweight racing engine for the Can-Am road racing series (Group 7), the original, solid-lifter 427ci ZL1 engine was never intended for production vehicles, but Chevrolet’s motorsports engineers never counted on an enterprising and forward-thinking Illinois dealer named Fred Gibb. He used Chevrolet’s COPO (Central Office Production Order) special-order system to produce the legendary Camaro ZL1.

Even though the engine made its mark earlier and continued to be used in racing into the ’70s, it was in those 69 ’69 Camaros—and a pair of Corvettes—that grew the myth of the ZL1. Over the years, Chevrolet stoked the embers, including a reissue of the aluminum cylinder block, which spawned a Ram Jet–topped ZL1 crate engine and an anniversary 427 crate engine.

ast month we introduced you to our ’66 Chevy II project, an all-original six-cylinder car that is being treated to a few modern creature comforts. We’re starting the upgrade process with a Vintage Air SureFit A/C system (PN 961166); you’ll see more of this car in future articles. In last month’s installment, we disassembled the cooling system, installed the condenser (and associated lines), installed the Steel-eez compressor bracket, and began prepwork inside the cockpit for the new A/C system.

This time, we’re wrapping up the A/C conversion by assembling and installing the Vintage Air evaporator and then completing the system plumbing and wiring. We added Vintage Air’s new Control Panel (PN 473272), which fits in the factory location and makes it completely electronic, instead of having to convert the original sliders to work electronically. The plug-and-play setup simplified the installation greatly, as did the E-Z Clip hose system (PN 547002), which allowed us to build our own refrigerant hoses without the assistance of a hydraulic hose shop.

After we buttoned up the install, we calibrated the new control panel. First, we turned the ignition switch to the “ON” position, then positioned the sliders to “HI,” “DEF,” and “HOT” settings. Then, we connect the white jumper wire to the gray program wire and wait approximately 5 seconds for the blower speed to change. Finally, we slide the controls to “OFF,” “DASH,” and “COLD” and disconnect the jumper wire. The blower speed should change again, indicating completion of the calibration.

hipple superchargers have been a popular option when it comes to making horsepower for years because their screw-blower designs are proven to make great power in a compact package. A twin-screw supercharger has an advantage over the roots supercharger because its design allows it to move air more efficiently.

The old-school roots supercharger uses the spinning lobes to move air along either side of the case and into the intake plenum. The air exits the supercharger at atmospheric pressure, so boost has to be built up inside the intake plenum.

Meanwhile, a twin-screw supercharger moves air in a cavity created between the screws. As the screws rotate, the cavity moves from the opening in the supercharger case directly to the exit. Meanwhile, the shape of the lobes on the screws also means the cavity gets smaller as the air moves closer to the exit, compressing it. That means the air is already under pressure as soon as it enters the engine.

e all deserve the best bang for our buck, and that goes for anything we spend our hard-earned cash on. When it came time to decide on an engine for my own project, I asked myself the same questions you would. Why build a mild-performance engine myself if I can go aftermarket (even with a warranty) and save a ton of time? My knee-jerk reaction was to opt for the aftermarket crate options. But, as with anything, the power of peer pressure can easily justify temptation. And … I’m glad I gave in!

hen the first Chevy II rolled off the assembly line in 1962, few people, including those at General Motors who designed and built it, would have guessed that 60 years later these cars would still be sought after.

The Chevy II came about because Chevrolet needed to fill a void in their product line. In 1960 Ford introduced the Falcon as a small, affordable option to a fullsize car. General Motors’ pre-shrunk auto option that year was the Corvair. But despite the fact the motoring press praised Chevy’s bold new offering (the Corvair was Motor Trend magazine’s 1960 Car of the Year), the buying public wasn’t as enthusiastic. By the time Ralph Nader expressed his disdain for the air-cooled, rear-engine Corvair, Chevrolet desperately needed a “Falcon fighter”—and the first series Chevy II (1962-1967) was it.