start bolting..
The list is almost endless to what you can add to the motor, just bolt on you can always upgrade injectors, and fuel pump. I always do those two together. If you have the money, full exhaust, throttle body, MAF, Injectors, and fuel pump, MSD 6, and coil.
You can do ignition first if your on a budget, but if you upgrade injectors i would recommend fuel pump, and MAF sensor at the same time, and of course a new fuel filter.
PS- If you are rebuilding the engine, add a DSS main support (Our blocks are only 2 bolt main, this support strengthens the bottom end beyond any 4 bolt main). Then your bottom end is built to handle serious power and abuse as you endlessly seek more power. Its never enough. I also added the windage tray.