Sorry to ask this question I'm sure has been asked many times but I need to be sure. When replacing the opti spark unit on a 94 lt1, is there any adjustment? Does the spline allow it to install only one way? What precautions should I take so I don't f*** this up. Thanks for any responses

Mike

 

A few things:

1) get a service manual to guide you, Haynes or Chilton will help a lot, and if you really want to get into things get a factory manual from Helm.Inc.
2) The optispark will only go in one way properly, but it can be forced in wrong if you tighten the mounting screws when it is in the wrong position. Wiggle things around till it goes in place without tightening the screws.
3) The optispark hates water, sho change the water pump out at the same time. You don't want to ghange the opti again after the pump springs a leak and wets it up.

 

here is a visual reference so you can see what the keyed spline looks like, and how to install correctly.

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