If prepared and tuned properly, you can run some pretty high compression on pump gas. I've personally built/tuned a 2.0 that had measured compression of 12.9:1. It was ran hard for 20k miles with regular service until 2004 when I closed my shop. Can't remember the numbers but it made something like 265hp @ 8300rpm. It was tuned using Hondata, a/f was like 12:1 under WOT. Can't remember the timing numbers, but I wanna say at 0 vac it was somewhere along 12-15 deg.