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.
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.
the advertising for this was enough to get people interested, but GM killed it fast.