I have a 94 camaro z28. My stock opti-spark currently went out on me. I'm looking to upgrade to a msd opti-spark. They have two models thow. A 94-96 late model camaro and a 92-94 early model with fresh air hoses. I was wondering what is the difference between the two. I wanted to order this opti-spark asap but I need to know which one I need. Summit and jegs did not help me answer this question. How can I tell if my opti-spark calls for the one with the fresh air hoses?? Does anyone have pictures between the two or something so I can compare my stock one to it. Or will either one work since there both for a 94 z28??

 

I bought the MSD, it works really well. The way you could tell which you have is check your intake elbow for a blue 90* vacuum tube going into the top of your boot. That should connect to your OPTI. If it's not there you have a nonvented opti. You could upgrade your cam and timing cover (I think thats all) and get the vented OPTI.

 

The reason for the confusion is the b-bodies got vented optis in 94 where the Vette and f-body didn't get them till 95.

On the MSD IMO you should not use it unless you have a keyed hub, degreed damper and have fabricated a timing pointer to verify it's setting. Even then the added "features" are meaningless to all but the most advanced users.

Consider putting a MSD cap and rotor on a stock base, this is a very good solution for most of us.

 

it has to do with the pin drive or shaft drive, its probably miss designated not sure if there was a mid year change from the shaft to pin drive.

 

I had to buy one because of my application. I bought 3 NEW OPTI's from the dealer and all three when the weather was above 98* and the car was at operating temp, when I would shut it off the car would not restart and would throw the opti failure CEL (I think high resolution failure). The MSD has been a much tougher distributer for my use. It's not perfect but it works and thats what I need especially as stupid as the LT1 distributer positioning is. The MSD also has 1 extra screw on top to seal better, so where the stock OPTI is 4 screws to hold the cover on the MSD is 5.

 

I had the non vented unit and the MDS pro billet is vented. The catalog showed the early one was vented and the later one was non vented so i hope they corrected it. Be sure to read carefully before you install as many have had them come apart and screw things up. There are tons of threads on here.