You can't raise health and energy any higher than that. At least, not without modifying the actual game code. Tron 2.0 is hard-coded to a 300 limit for both.
The God mode cheat effectively gives you unlimited health and energy, anyway. You never need additional health, and the only time you use energy is when you download something. Weapons use no energy with God mode enabled.
The Killer App Mod
improves on God mode by making it permanent, so you don't keep having to type the cheat code every time a level loads. There are also options for all permissions on every level, and full gold subroutines at the start.