more bottom end power

[nismo300zx1990]

hey guys I have a 1990 300zx na and I have done some mods to my engine. I have bored out my block 60 over which is not a whole lot, new pistons and rods, JTW cams, ported and poslished heads from z1motor sports, headers and full cat back exhast, aluminum one piece drive shaft, new after market fuel rails, egr delete kit. pretter much everything you can do to a na other then putting a tubo on it which in hind site I really wish I would have done. Anyway my car now is not as fast as i remember on take off and it seems to really take off around 4k rpms. Is there a way I can have some more bottom end? maybe around 2.5k or 3k rpm?

thanks for your replys

[DCaff300ZX]

Your problem lies within the fact that the NA engine is pretty much maxed out as-is for best operation, and as you touched on Nissan's answer for more power is forced induction. The Z32 engine is already a fairly peaky motor which is why they used the variable valve timing for more BOTTOM end power, as it already flows and breathes well enough for it's top end needs, and so adding the cams you did just made that moreso while stealing from the low end to do so.
You can undo your work (cams most likely) to some extent for a better power balance, but you basically have about 250HP to throw around wherever you want...not a lot more, and not able to be placed specifically unlike a TT and tuning.
This is partly why the phrase "just buy a TT" has come about, along with the fact that turbo-ing an NA does very little and will most likely nuke the high compression NA engine.