Pretty interesting (and ambitious) project you've got there. From the parts you've listed it sounds like you have some money to spend. For 600-700 hp you definitely want more than 383 cubes. Dart sells a nice block with splayed main caps and comes with a 4.125 bore with capability of 4.165 while maintaining .230 cylinder wall. If you want normally aspirated power, there just ain't no replacement for displacement. You can easily obtain obtain 434ci in a small block package. Personally, I wouldn't strive for a 7500 rpm small block for street use just for the sake of longevity. At that level you will be building a race car engine. Also, your cam selection uses a 106 degree lobe separation angle. On a carbureted engine this can boost torque creating better cylinder scavenging due to the intake and exhaust overlap. This also creates a phenomenon called reversion at lower rpm. Fuel injection does not like reversion. Carbs are not as sensitive to this as FI. If you check cam specs for high performance FI factory engines such as the LS7 Corvette and others you will find LSA's in the 110-114 degree range. Learn more about cams and valve timing, too much duration and/or overlap can make an engine no fun todrive on the street.