ran it 10 times, no luck, my Battle Power is 12,663 though

I did it using Hinata, Sasuke, and Kisame, both healing mystery and passive, healing tips, soul steal, and water style- shark bomb jutsu and hell dog summon. Might also work with Shiba summon, but the key was the excessive healing power.
I've also done it once with Kabuto, Neji, and Guy.

These tips from 67 lvl to beat 70 exam... *facepalm

I mean a 67 can beat level 70 exam, and it's not particularly difficult to do. I'm currently working on exam 86 as a 75. I've found that most people can do exams somewhere between 5-10 levels above them, though I do know some people that are on 90 at level 76, though that is mostly earth mains.

Ermm, the lvl 70 exam is very different from the lvl 70 mission. Sure, people of lesser levels have been able to beat levels higher than theirs, however this is usually because their power is particularly or because of a certain team combination. When I was trying to beat lvl 70, I tried things like building up power and moving up levels. Even when I was at 16K and lvl 72, I STILL couldn't beat it. The key (at least for me) wasn't power or moving up levels. It was using ninja who could use acupuncture/paralyze so that Tobi and Deidara (plus his explosive spiders) couldn't attack.

TL;DR -- Try a different combination of ninjas who can stop their opponent from attacking via acupuncture, paralyzation, ect. I manage to get by w/ my 4 star water mc, 4 star Shikamaru, 4 star Naruto, and a 3 star Neji. I forewent the healing powers altogether and kept the water shark mystery attack.

Done it at 55 as firemain and some op ninjas. All i wanted to say that your tactic wont work for ppl below 65 or so. Unless they pump their characters a lot with cash.