I have a 1993 trans am with a 5.7 lt1 v8
i had to change to optispark so i pulled off the harmonic balancer and i marked witch way it up but that mark came off and its not keyed. if i put it in the wrong way the car will shake horabley. i looked at the end of that crank and all that is there is a little think that says gm and a notch. does that notch indicate top dead center? and on my balancer there is writing and a arrow. does that arrow face tdc? if it did it would face that notch but i am not sure and i can't find anywhere that i can find it

 

that would make sense, however this is a site for 3rd gens, 82-92.

Maybe ask the question in the ltx/lsx swap board in the engine forum, or try ls1tech or other ltx/lsx sites.

 

It's neutrally balanced, you can put it on in any orientation.