Has any one converted an unvented opit to vented, or, am I the only one brave or dumb enough to try it. I have some of both kinds, I plan to drill holes and insert tubes in the unvented one similar to the vented one. Anyone know why it won't work? Give me some feedback. Danny Mc

 

You will need a new timing cover, new timing gears, new camshaft (unless you are already running an aftermarket cam with the larger pilot hole in the nose), longer dowel pin, new harness between the connector on the side of the intake manifold and the opti, vacuum harness. There's an online guide with all the parts numbers and explanations. Maybe someone could post the link for you.

 

That was true up to a few months ago. However, with the advent of the MSD early model distributor, number 8381. You can now have the old style drive 93-94 and still have a vented system.

http://www.msdignition.com/2006/06-4.htm

Pull up the instructions for the 8381 in PDF format.

If you don't want to replace the distributor with a new one, you can also modify the old one as shown in this write up.

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

In which it shows this.

 

I basically followed the link above but only did one outlet on the bottom. Saw no reason to open all 3 holes.

 

Neither of those methods replicates the vent system provided by the factory vented Opti.

If you connect only to the cap, you will not have the "cross-flow" that the stock design provides, with the air inlet to the main body on one side of the dividing plate, and the vacuum on the cap, on the other side of the dividing plate.

 

Both methods ?

I only saw one method of modifying the old unit. And it did address the cap and the base to seperate sources.








The MSD unit (I wouldn't call it a "method") but what ever you call it, did as well. If you look at the pictures closely.

After looking at the MSD unit PDF instructions carefully, if I have it wrong please instruct me.