i heard people say the shock TACH is not very accurate. but since your new tach should be reading off the same wire, i dont know why its off. how much is it off?

i might be reading your second question wrong, but it doesnt matter what numbers go up to on the tach. my speedo goes up to 140mph, but i doubt my LS can go that fast.

see if you can really rev till 10k...=P