Everyone knows that nartuo has great stamina and a huge amount of chakra so he just keeps going and going when others are tired but i was wondering, is this because of the nine tails chakra or his own?

cuz earlier in the anime kakashi says how his wounds heal fast by the kyubi's power and i always thought that naruto having lots of stamina is an unfair advantage cuz he has kyubi in him. but now they say he couldnt access this chakra unless he does a special thingy like he did in ep 62 so naruto has a huge chakra all on his own?
and maybe another wondering, will he be as strong without the kyubi in him?