New LS1 Owners - Newbie Tech - Underdrive pulley question LS1

I am going to put an Underdrive pulley on my Wife's 99 T/A. It is my understanging that the crank on a LS-1 is not keyed. How do I line up the new pulley?? Can it just go on anywhere? I am assuming this thing is nuetral balanced. It is a SLP underdrive pulley if it matters.

Goes on anywhere.

Just get the proper puller, use a lil trans oil and make sure it seats fully.

Did you put a cam in it yet?? If not I would consider it now as it is a double job if you do it down the line.

No the crank isn't keyed. The balancer may be marked with timing lines but that would be up to you whether you line those up for future use later. I just stuck mine on and didn't worry about the marks.

Sorry to jack thread but if you replace UD pulley what all else would you need to change as not to change anything else like alternator output and such?

put a smaller pulley on the alt

You need a pulley bolt as factory is TTY and I changed no accesory pulleys but because of my cam I idle a litte higher. I still don't think it necassry though. Also will need a shorter serpentine belt...

If you have an A4 and idle is still stock, you charge may drop a little at idle especially with lights, and AC on but no biggie. I didn't put an OD Alt pulley on when I did mine because I plan on doing a cam and will have it tuned for it at that time.

is the the lower pulley a harmonic balancer also ?

yes and no LS1's are internally balanced