We probably don't need to explain the woes of vacuum-actuated headlamp rotation to any of the '68-82 Corvette owners out there. If you own or have been around Sharks for any time at all, you're undoubtedly familiar with the shortcomings inherent with the vacuum system that rotates the C3 headlights (and windshield wiper door as well on the '68-72 models). The vacuum system tends to be every bit as vulnerable as it is complicated, and it's prone to lose performance if not outright failure.

Over time, the rubber hoses and other components of the vacuum system age and wear out. Also, the headlamp rotation gets slower and slower and inconsistent, and the "frog-eyes" begin "winking" at you (one side rotating faster than the other), until at some point they simply wink out. Most of the vacuum system components are being reproduced and are available on the aftermarket, and we walked through the process of restoring the vacuum system on a '72 Corvette last year ("Into the Void: Parts I, II, and III," Dec. '02, Feb. '03, and Mar. '03). But what if irreplaceable components, like the master vacuum reservoir on the early Sharks, won't hold pressure or you have a big motor or a hot cam with a lot of duration that doesn't create much vacuum in the first place?

Well, it's no longer necessary for those vacuumless Sharks to live out their days--as well as nights--with the pop-ups fixed in the open position. Chris McDonald of McSpeed Performance designed a way to replace the stock vacuum setup with late-model GM electric headlight actuators using his '69 killer Shark roadster (see "The Need for McSPEED," Mar. '03) as the guinea pig, and he has created a kit to make the conversion as simple as possible. The McSpeed Killer Lights kit includes all the brackets and hardware necessary for mounting a Fourth-Gen Pontiac Firebird electric actuator system on any C3 Shark. Then, depending on how much time and/or money you're willing to spend, you can search for the necessary used electric components (even many worn-out electric actuators can be rebuilt, as we will illustrate), simply pay a visit to your local GM dealership's parts department, or a combination of both.

Michael Meyers, President of Dreamworks Performance Engineering in Sheridan, Colorado, was happy to provide his highly modified '75 Shark ("Feeding Frenzy," Aug. '03) for our installation. Since he's modernized so many other aspects of the '75, Mike's Shark seemed like a natural to us for this update. Instead of scrounging around for used parts, which is a completely viable alternative for those individuals willing to devote the time, we opted to order all the necessary components that Chris recommends from Purifoy Chevrolet in Fort Lupton, Colorado. Although we are starting with brand new actuators, the nylon gear that GM installs in the Firebird actuators is notorious for wearing out. (Yup, it's the same fragile kind used in C4s and C5s, as well.) We decided to preemptively fix the weak links by replacing the standard nylon gears with virtually indestructible CNC-machined brass cogs from Brent Franker before installing the new actuators.

With the conversion complete, the '75's headlamps now speed immediately up and down with no sluggishness, no delays, and no issues about going one at a time--and the motor doesn't even need to be running! Finally, a solution to vacuum that doesn't suck!

SOURCE
MCSPEED PERFORMANCE Purifoy Chevrolet
www.purifoychevrolet.com
DREAMWORKS PERFORMANCE ENGINEERING
3301 W. Hampden Ave., Unit P, Dept. VM
Sheridan
CO  80223
Brent Franker
www.bfranker.badz28.com