I have a 95 corvette lt1 that I'm rebuilding the engine on. It has a vortech supercharger, and when it was installed, the stock optispark vent set up was unusable, so it was left off. Bought a new msd cap and rotor kit and it doesn't come with it. The parts store shows they can get the kit but it doesn't look like I'll be able to hook it up with out some direction. Any one with an idea of how to do it please help. My stock cap and rotor were corroded bad, and the metal shield is starting to rust. Due to the location and all the mods needed to do the vortech, I don't want to even think of getting to the distributor again. The stock air intake is gone where I think one of the vacuum hoses go to. It's replaced and is under boost so it won't work as a vacuum. I have a place to tap into the manifold vacuum but really need the little filter and check valve, I'll make up my own hoses. Just need the routing and parts mentioned. Thanks
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If you're able to return the cap/rotor you have and get the MSD 8481 kit it will have everything you need. It's sold as a retrofit kit for unvented Opti's but will work perfectly fine on yours. Otherwise you can usually get the vacuum filter from the parts store where they keep all the miscellaneous Dorman stuff.

The larger of the two vacuum ports on the cap is for the manifold vacuum port. The other is the fresh air side. On stock setups it goes to the air intake tube.

 

I bought the 93/94 kit but the cap and mounting plate are different. The 95 has the metal nipple on the bottom of the distributor already. I returned the kit and got the correct kit but it doesn't come with the parts for the vacuum. What i need to know is does a hose go from manifold vacuum to the distributor and a check valve between, and the cap vent goes to the air intake? Or should I just leave it alone and run hoses to vent both cap and distributor to the atmosphere while keeping water from getting in. But then there's still the problem of condensation. I'm wondering why the shop that installed the vortec left the kit off in the first place. MSD cap and rotor are over $220 and don't want to do it again. I'm going to silicone the ign wires to the cap because the terminals were corroded, another $230 for new wires. And thinking about a fine amount of silicone around the cap to mounting plate, and mounting plate to distributor body o rings to seal it up for good. Maybe I'm overt thinking all of this.

 

You have it backwards-the metal nipple is for the fresh air and routes to the air intake tube (that was taken off for the supercharger). The dist cap nipple is where the vacuum line w/ the little check valves (there are two on a factory setup) runs to the vacuum port on the side of the intake manifold. That should be present for you unless you no long have the stock intake manifold. I attached a pic from an FSM of the vacuum port location on the intake.

Good question. Did they just cap the vacuum nipples on the cap/dist body? This is probably the reason everything is so corroded.

I looked up the Vortech manual for install on a C4 LT1 - I linked it for you to make sure it's for the kit that you actually have on the car. That manual has a note on pg 26 about the fresh air line to the air intake tube. It doesn't say anything about removing or doing anything with the vacuum line to the manifold. Vortech Kit

Maybe someone that's done the install on a 95-96 can chime in to help. I don't know much about the kits other than what's in the install guide.

I wouldn't silicone the wires. Also, why are they $230? LT1 wires are expensive but that's insane. Some people silicone the cap in addition to the o ring that's there. I think it's unnecessary if you have the vent setup.






I hope this helps.

 

The shop that did the blower never hooked it up and left it open. I can probably make something work with the diagram, thanks. If I just capped the lines it would probably still corrode from condensation. As for the wires the MSD 8.5 wires made for the 95/96 are over$220. My whole ignition system is MSD with the exception of the stock distributor with the Mitsubishi optics and was rebuilt 10 years ago when the blower was installed. It ran great until a catastrophic overheat on the hiway. Blown headgaskets,water pump failure, and two wires burnt through. So, as of this day, I still don't know what caused it. I'm paralysed on most of my left side, and if I'm lucky, I'll get it done by the end of the year. My last non stock car ever. By the time I get it running I'll have 30 grand in a 20 grand car on a good day. It's a really nice ground up everything new car but I can't take care of it due to prices of parts and my health. Thanks for the info. I'll let y'all know by Xmas how it turns out.