So according to your comment the CP of your Pokemon is:
And your dragonair has more perfect IV stats than your dragonite.
Then this should be easy then. If your Dragonair has more CP and better IVs, then it beats Dragonite pretty easily. If you evolve Dragonair, it will still be powered up so you wouldn't need to power-up your other Dragonite, so you will have both 2 perfect IVs and a high CP dragonite.
However, I suggest waiting because remember, you might find stronger Dragonite/Dragonair/Dratini while searching for Pokemon. Also, I notice Pokemon with higher CP gain more CP evolving, so I also suggest that you power up your Dragonair befrore evolving. If your still hesitant, then tell me the moveset of both of the Pokemon and which IVs are perfect.
BTW I really hope you didn't mix their CP by accident. Other than that, hope I helped! If not, I'm sorry.