I found a couple other things that are odd while replacing the opti. Firstly, when I removed the opti from the front of the car, I noticed that the little spline drive stayed IN the spline hole on the front of the engine. I found it odd, because on the replacement opti, the spline drive looks to be an integrated component. I pulled the little spline gear out with my fingers -- i guess 93/94 spline driven optis were 2 different parts?

Secondly, I noticed that there was some oil and gunk in the busted opti. It looks as though this oil had come in from the place where the spline drive interfaced with the opti itself. However, I'm not sure what seal this would be!

All the write-ups i've found detail the 94/95+ seal replacement, but I'm not sure how to attempt the opti seal on the 93/94. It looks as if the oil is seeping from where the spline interfaces.

Does this indicate that I should replace the entire timing cover gasket? It doesn't appear to be leaking anywhere else...

Any help would be most appreciated -- I am planning on tackling the re-install tonight so I can get back on the road!
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U can buy a Felrpro timing gasket set from Autozone for 15.00,it comes with opti seal,water pump seal,crank seal and timing cover gasket.The opti seal is very easy to replace,just pop the old one out and tap the new one in place.I would also replace the crank and w/p seal as well..In the felpro set I believe the opti seal is green in color..Is your new opti a MSD opti?If so you are correct the spline is "built into the opti"..

 

Not MSD, no -- it's an El Cheapo "TSP" Brand opti. I modified it to be a "vented" style (drilled out one of the bottom holes & swapped on a vented cap. The little opti seal on the splined version is different from the other write ups i've seen on the net -- i just wish there were some pictures of how to do it, or some acknowledgement that the seal is different as well as the opti.

 

The drives on the unvented opti's are different in comparison to the vented opti's, and I would guess that the seals are different as well. I'm pretty sure the opening in the timing cover and the associated seal are much larger on the vented units.

I found this. Maybe it will shed some light on the differences. LT-1 Ignition System - Understanding, Modifying - GM High-Tech Performance

Replacing the seal should be fairly simple. It wasn't difficult on my '94.