Once you have the basics taken care of you should be able to get around 15-16psi on pumpgas. For some reason me and my dad could run 20psi with a degree or so of knock only on the 1-2 shift. Don't know why but I've heard of other people being able to run a lot of boost on straight pumpgas with the hotairs. 20psi is about as far as you want to go or you will start slowing down even if it's not detonating. At that boost level at the end of the 1/4 mile the charge air would be around 320 degrees. With very basic mods like fuel pump, regulator, K&N, boost, and a chip you should be able to get into the upper 13s on street tire.