Go to an auto junkyard. I always see at least 2 or 3 S13s with the analog. get the wiring harness for it from the vehicle. Everything should work, unless you pull it from a 89-90 S13 and put it in a 91-94 S13, or vice versa. In that case, you can take the tach that works and swap it with the tach that doesn't.
"Tonight we ride, and for those about to rock, I salute you." -Jack Black, School Of Rock