The engine bay of a '94-'96 Caprice/Impala is easily the most spacious of any LT1-equipped car, yet it can still be intimidating, particularly if you're not one to wrench on late-model stuff. Buried in there is the Opti-Spark ignition distributor, itself a bit of a fearsome device, but servicing it is no big deal, as you'll see.
Man, time flies. It seems like just a couple years ago when GM introduced the first major renovation of its small-block, but of course, that was back in 1991 for the '92 Corvette. At the time, one of the big deals of the Gen II engine was the Opti-Spark ignition system, which was driven directly off the cam and treated the engine "like eight one-cylinder engines," according to GM, in reference to the system's agility in constantly adjusting ignition timing based on need. The Opti-Spark system still used a distributor and conventional spark-plug wires, but it seemed to be considered a maintenance-free device, at least if the 100,000 spark plugs were any indication. But now the youngest of LT1-powered cars have been on the road for about nine years, and it's pretty common to see them with well over 100K on the clock. What's more, time has shown that LT1s tend to be hard on their ignition systems, if only because the plug wires are routed behind the exhaust manifolds where they are frequently baked prematurely. The resulting increases in resistance can in turn stress the distributor cap, and that's where a lot of guys get hung up.
If it isn't the fear of the unknown causing hesitation in tearing the system open, it's the lack of available parts, or at least their unusually high cost. Apparently, since GM didn't intend for this system to need frequent maintenance, the cap and rotor were not initially available on their own, and a whole new Opti-Spark unit had to be purchased. Later, the cap and rotor were sold separately, but often at a price that made the complete Opti unit seem more attractive. Now MSD has stepped up to offer its own version of the Opti-Spark cap and rotor, and by the time you read this, a complete, billet-housing Opti-Spark distributor. Both the cap-and-roller sets and complete distributors will be offered in early and late designs to cover all LT1 applications. We'll tackle the simple tune-up parts and illustrate that getting the job done on a Caprice/ Impala, isn't so bad. Have a look.
Within a few minutes, and with a few twists of a flathead screwdriver, the air inlet ducting and radiator hoses are removed (obviously, make sure the car is cool first), making the front of the engine a little less cluttered. The bad news is the water pump, air pump, and crank balancer all have to come off to get to the Opti unit, but it really isn't that tough once you know where the fasteners are and the removal procedure. | 
If GM hadn't used one of the water-pump bolts as a mounting stud for one of the air-pump bracket's mounting ears, the air pump could stay in place while the water pump comes out, but it did, so it does. There are three bolts holding the electric air pump to its bracket--a 10mm socket easily removes them, and then the pump can be swung out of the way with its hoses and wiring intact. | 
The air-pump bracket has three mounting bolts, and a 916 will get them if you don't have a 14mm socket. The bolt over the water-pump stud accounts for one, another is in the center of the bracket, and a third is tucked behind a spark-plug wire. Pull the second wire from the top on the left bank and stick the socket through to the bolt. |