I have a question regarding the Optispark distributor on 1994 LT1's. Were all '94 LT1's spline driven? Or were the later models pin driven? The reason I ask is the following quote from this article

If the LT1's were different in the '94's, what's the best way to tell which flavor you have aside from removing the OPTI? Can you tell using the build date or VIN Number?

 

Someone please correct me if I'm wrong, but I believe the change from non-vented to vented Opti's happened late in the 94 model year. So if your Opti is non-vented, get the earlier version. If vented, the later version.

 

OK. If it's vented there would be a vacuum hose running from the distributor?

 

Correct, Although I havent seen ANY late model 94's without the spline driven optis. All the 95's and up have the clover leaf design in the back which is the vented models.

 

Vented optis did not begin in f-body cars until 1995. Everything earlier was non-vented.

 

Gracias

 

I have a couple more optispark related quesitons.

Are all of the GM manufactured optisparks still the original design? I noticed that someone had gotten a GM Performance Parts optispark and was curious if it's any different than what came from the factory. I think the GMPP optisparks for my car are around 400 bucks. I had pretty much decided that if necessary I would spend the extra hundred and get an MSD for the venting and timing adjustment. Now I'm not really sure what I should do if I end up needing to replace the distributor. Approximately how much do those LTCC setups cost? Is that more of a racing configuration?

Maybe the MAF & O2 sensors will be the source of my problems, but I think there are probably other things at play. Would a bad Opti start great, idle fine, sputter around 1500 rpm, but otherwise rev fine when not under load and then have you thinking your car is going to explode when you actually try to drive it? I probably never got above 1200 rpm's in first gear and I definitely felt that I shouldn't try. It was missing, backfiring etc. It sounded really bad.

 

Just so it is noted because this caused confusion with the parts sellers, the b-bodies(caprice Impala Roadmaster) and d-body(Fleetwood) got the vented opti in 94,ALL of them did. I think this is the source of the confusion in catalogues as far as what opti fits what year.

 

So, the LT1's that went into those cars got the newer, pin style camshaft while the f-bodies just got the shaft?

 

I only know of one part number for each of the two GM optis. No "performance" opti.

 

Exactly why I stated f-bodies in my previous post.

 

I was not trying to correct anyone just adding info and shed light on why I believe there is confusion on the 94s as far as vendors and catalogues are concerned.

 

I have a VERY late 94..... one of the last ones. It had the splined drive/unvented Opti.

 

And, just to complete the alphabet soup, the Y-body got them at the beginning of 95 MY, same as the F-body.

 

Two of them. But an unvented opti could have a hose or hoses added to it. So absence of hoses is reasonable proof of Gen I opti, but presence of them doesn't prove anything unless you know it's untouched.