I seen a thread on here a few months back where someone added some fittings to the bottom of there 93-94 opti vent holes along with some vacuum hose to help vent there opti. i wasnt sure where they ran the vacuum line to on the motor? anyone remember or know a place to run it to??

 

http://www.corvettefever.com/howto/16758/index.html

Or you can just buy an MSD cap and rotor for the non-vented opti. It incorporates it's own and similar venting system.