I would shoot for low 14s for now. Get a little more comfortable with your setup and your racing abilities and then shoot for 13's.

I hope you get it tuned with a standalone ECU and race fuel before racing it because of the very high compression. Once you chip out an ECU, it won't matter if it is a P73, P72, or P28. Save yourself the hassle and chip out an OBD1 P72 for the tuning program of your choice.