All Motor in an LS in your teggy will take some $$$ to hit 13's. It can be done. A guy that I know off of clubsi.com (HXguy) had a all motor civic hx 97 i think, it was all motor and non vtec and he hit 13's pretty easy. But he had a 2.0 bottom end, shorter gearing, head work, and it was tuned out, and I believe slicks as well. He eventually put a vtec head on it and I think it hit 12's for sure.
Milan