87Aerocoupe

As the title states are ther any differences between the optispark distributors for 94 and 95-up? IIRC certain years had a splined drive which required a different cam and other years had a long drive pin, also some were vented and other years weren't.
I may be getting a 94 Z28 and I want to use a vented opti and the LTCC and I have a h/c LT1 that I want to put in it which has a double roller timing set and the cam has the long pin to drive the opti and I want to make sure it will work.
If I do need to buy another opti which one is best and ebay one, GM or MSD considering with the LTCC swap it really is just a trigger?

shoebox

http://shbox.com/1/93-94_opti.jpg

http://shbox.com/1/opti_back.jpg

A genuine GM opti is the best value. thepartsladi on Ebay has been a good source for many people.

If you want to change to a vented from non-vented, you have to do many things. It may not be cost effective unless you are doing a cam swap at the same time.

Besides the optispark itself (GM p/n 1104032), you need:

• 95 or later timing cover [1995 front cover (includes round seals) GM p/n 12552426]
• late model cam (or have your cam modified by drilling the hole in the front to the proper size [.500"dia. X 1.0625" deep] and a longer dowel pin added
• 95 and later optispark electrical harness GM p/n 12130319
• optispark vacuum harness GM p/n 12555323
• vacuum fitting [GM p/n 14082470] or "tee" to provide vacuum for the opti
• 95 or later timing set components (or at least the cam gear) cam gear (GM p/n 10206039), crank gear (GM p/n 10128346), chain (GM p/n 10128485)
• timing cover gasket GM p/n 10128293
• water pump gaskets [2] GM p/n 10128343
• intake manifold gaskets if you are pulling the cam GM p/n 12524653

96capricemgr

The reason the opti needs venting is because of the ozone created by the spark. If you take the spark out of the opti by going LTCC it seems a bit unnecessary to do the vented conversion, unless you have the part laying around.

In 94 the Vette and f-body still had the unvented setup but the b-bodies got the Vented which causes a lot of confusion.

87Aerocoupe

Thanks guys that info is most helpful the reason for the swap is I may be buying a 94 Z28 but I have a 95 LT1 with home ported heads & intake, Holley 58 mm tb, Pacesetter LT's, Comp 230/230 - .560/.560 110 lsa cam with the long drive pin, New Comp 875 lifters ( the good ones with the snap rings). Rollmaster double roller timing set,95 timing cover, new Canton oilpan, new oilpump, all new gaskets & seals and CSI ewp and one of Shon Herrons billet oil pump drives.
I want to put this engine in the 94 so I'm sure I'll have to chang the opti so I should be able to get buy the the ebay unit.

96capricemgr

You can use the unvented on a 94 just need to set things up for the unvented. Sounds like the engine is setup already, now I think it is just a slight rewiring of the opti harness.
It is not like the electronics are diffetrent and incompatible or anything.

87Aerocoupe

Cool beans thanks Dwayne.