HMMMMMMMMMMMMM

I personally think you have a problem, it should run much quicker than that. DONT USE YOUR NITROUS NO MORE, you have problems bigger than that, ill give you some things i would check

Check fuel pressure-WOT and at idle
Check timing- are you setting it right? what is your overall timing? advance working?
Check plugs- see what they are burning like, possibly too lean, are your secondaries working properly??
Check for weak spark
CHeck to make sure when your pedal is mashed, that the butterflys are completely open

these are simple things but i think its a timing issue or carb prob also, yes gears would help and traction is critical but 16s is not what you should be getting. I think your gonna grenade that motor if you dont find out what the deal is first ESPECIALLY if your carb isnt tuned properly. good luck and keep us posted

-nova