The .030 over is not a hard and fast rule. Sonic checking will tell you. But these are thin wall casting and your short block may be done. If there is no scoring or taper you may be able to get away with a hone and rings.
You didn't mention your budget. "the more power the better" can cost a fortune. You indicated that you want it to run on pump gas so I am guessing you want to keep it streetable. 450+ is not a problem with a medium size budget while keeping the engine streetable. More than that you will probably get into bigger heads, wilder cams, etc. More money.
There is some good information as well as sample builds at this site:
http://stangstable.com/
Rick