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1970 GTO with Vacuum-Operated Exhaust

Details from the VOE repro system.
Details from the VOE repro system.
KC Classic

Nineteen seventy is considered the high-water mark for muscle cars, but it really depends on the brand. For Chevrolet, the LS6 454 debuted in 1970, but was it really better than the COPO Camaro from the year before, not to mention the L71 and L88 Corvette? The same argument could be used for Pontiac, as the high-performance OHC-6 Sprint and 428 HO disappeared after 1969. But 1970 also marked the debut of a redesigned Firebird, a GT-37 to compete with the Plymouth Road Runner, and the "Tiger Button," otherwise known as "W73" Vacuum-Operated Exhaust. One of these rare cars is currently on eBay.

This is one of 212 GTO hardtops built with the VOE system.
KC Classic

The VOE, which was available only on the GTO, can be counted among the coolest gimmicks to emerge from the era. The concept was simple: Baffles in the mufflers could be controlled via a cable under the dashboard - the growl coming from the motor was controlled by the driver. Pretty neat, eh? It's claimed that John DeLorean originally had wanted the system to open the mufflers, advance the timing, and open the Ram Air flaps, but the production item was nowhere near as complicated. The VOE was made famous by this GTO commercial that ran during the Super Bowl.

Supposedly, the option was only available with the standard 400/350 motor and possibly the optional 455/360; none of the Ram Air motors were available with VOE due to the radical cam and, hence, lack of vacuum, although there are rumors that a few were built. In the commercial, you can see the bracket is also shared with the Ram Air cable, but chances are this car (which also appeared in the dealer brochure) was a cobbled-up pre-production vehicle. All told, 212 hardtops and 21 convertibles were built with this option before it was cancelled in February.

There's some discussion about this car on eBay because of its build date - if the option was cancelled a few weeks after the Super Bowl, why was this car built in April? The invoice from Pontiac Historical Services and the build sheet shows it to be legit. There could be a good explanation how a car like this was built, such as one GM employee's comment that ". . . when an option is killed, the program team has the prerogative to either run the existing order bank out or reject those orders back." It would behoove a serious buyer to order his/her own PHS document to make sure it hasn't been forged.

If the eBay ad is still up as you read this, you'll notice the seller states, "Dressed in striking Atoll Blue paint with exclusive VOE striping," but that's not quite correct, as the D98 stripes (which was simply the beltline stripe that was on the 1969 Judge) were a separate option and not connected to the VOE option. In this car's case, they didn't come with them originally per the build sheet.

NOS VOE sets are extremely rare, but if your GTO is one of the rare few born with VOE, or if you're tickled enough that you'd like to install a set on your Goat or even Brand X, check out the Waldron's Exhaust website.

Old cars are cool - that's why I write about 'em, and that's why you read 'em! So visit my index to read more, and email me with automotive suggestions to keep you entertained.