MSD Pro Billet LT1 Distributor - The Final Opti

MSD Pro Billet LT1 Distributor - The Final Opti.OptiSpark. The name alone is enough to give '92-'96 Vette owners the jimjams and send even the most jaded auto techs scurrying for their shop manuals. Indeed, with the possible exception of the ill-starred "Crossfire" injection system of the early '80s, no single piece of engine hardware has heaped more ignominy on the Corvette's exalted powertrain history than this legendarily perfidious crank-triggered ignition unit.

That the OptiSpark turned out to be such a stinker is all the more disappointing in light of the technologically vanward thinking behind its basic design. By keying spark events to the crankshaft, the front-mounted Opti was able to provide a level of timing accuracy far superior to that of any conventional, top-mounted ignition unit. But when it failed-and boy, did it fail-the car's drivability tanked, leaving owners facing a host of drivability issues and a roughly $1,000 repair bill.

Fortunately, MSD now offers the Pro Billet LT1 distributor, a comprehensively upgraded OptiSpark unit designed to fit all LT1- and LT4-powered Corvettes. We covered the Pro Billet's particulars in a previous article titled "The OptiSpark Option," which appeared in our November, 2006 issue. This month, we offer an overview of an installation recently performed on this author's Polo Green '96 Coupe.

MSD LT1 Distributor Optispark Replacement
Here's our stock OptiSpark...

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MSD LT1 Distributor Optispark Replacement
Here's our stock OptiSpark unit prior to removal. Given the amount of crud that builds up on these things, is it any wonder they're prone to failure?

Because of the rather involved nature of the job, we strongly recommend having it performed by an experienced, Corvette-savvy mechanic. Fortunately for us, the folks at Brandon, Florida-based tuner Rev Xtreme had performed a number of Opti swaps over the years and were more than happy to help out. The highlights of the installation, performed by Rev X tech Kyle Briese, are included herewith.

In addition to its bright-red... 

   

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In addition to its bright-red cover, the MSD Opti can be distinguished from the factory unit by its extra-thick billet-aluminum base...

...and timing-adjustment screw.... 

   

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...and timing-adjustment screw. The screw makes it possible to advance or retard timing by up to 7 degrees, something not previously possible on LT1/LT4 engines. We didn't fiddle with the timing for this test but plan to do so in the near future, when we subject the car to a dyno-based custom PCM tune.

Here's a shot of the Pro Billet... 

   

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Here's a shot of the Pro Billet LT1 distrib-utor, sans cover. Note the beefy molded rotor, with its brass/stainless tip. The O-ring on the right helps repel moisture, the leading killer of factory Opti units.

To ease plug-wire routing,... 

   

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To ease plug-wire routing, Rev Xtreme tech Kyle Briese marked firing order on the Pro Billet's cover with a Sharpie before installing it.

The MSD plug wires were too... 

   

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The MSD plug wires were too thick to fit in the stock looms, so Briese cooked up this nifty Zip-tie arrangement. It's clean, it works, and it's the very definition of low-buck.

This photo shows why braised... 

   

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This photo shows why braised plug-wire boots are a common problem on LT1 Vettes. Fortunately, the boots on the MSD wires are significantly more heat-resistant than those found on typical parts-store replacement jobs.

It's a wonder our stock Opti... 

   

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It's a wonder our stock Opti worked as well as it did. This screw had worked its way loose and become lodged in the path of the rotor. Believe it or not, Briese tells us this is a common problem with the factory unit.

Once the installation was... 

   

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Once the installation was complete, the Rev X crew performed a couple of pulls on the shop's in-house chassis dyno. While the car failed to improve upon its previous best horsepower and torque numbers (which, we should point out, were taken on a different dyno), it did seem to pull harder and more smoothly at high rpm levels.

While we didn't see a horsepower improvement with the MSD Opti, the modified car did seem to pull with more verve in the higher rpm ranges. Furthermore, we expect the MSD unit's timing-adjustment feature to prove a real benefit as our modification regimen intensifies.

In the meantime, the Pro Billet LT1 distributor's reasonable price tag ($515-about $200 more than a factory replacement), top-quality features, and ironclad reliability make it a welcome addition to our budget-oriented '96. It may be late in the game, but thanks to MSD, installing your final Opti is now a reality.