the raikage imo, minato hasnt shown anything string enough to beat it. one things for sure is his rasengan is useless if rasen shuriken didnt do crap. and minato beat a weak madara for the last time, he wint stand a chance against this madara, even minato said it will take special powers to beat him. and kishi never said minato is the strongest, thats what jman said, iruka said 3rd was strongest hokage. everyone has something diff to say.yes 3rd raikage is powerfull but minato is the strongest dead ninja even kishimito says that.we dont know minato full powers, however what we know about him was good enough to beat MADARA UCHIHA, the ninja everybody is afraid of, plus minato beat A and killer bee together.
well 9 tails is really stronger then the 8 tails. also minato didnt really lose. he knew tht the masked man was madara and he knew tht madara is more dangerous then the 9 tails and tht the only way to defeat madara was with a special power which is why he sealed the 9 tails into naruto. minato actually didnt even have to die. he only died so tht he could seal naruto mothers chacra into naruto so she would be able to talk to him once more in the future. kushina said it herself tht minato did not have to die. so saying he lost to the 9 tails really is nt true... for the record im going with minato because he is faster do to ftg (and i know this isnt raw speed but his reaction time makes it so tht its better then raw speed) and hes a freakin genius so im sure he would find away to get past raikages shield. also he has a bunch of sealing techniques and other techs we have nt even seen yet. knowing this and the simple fact that kishi himself said tht minato was the strongest dead ninja id have to conclude tht minato is stronger. and i know tht kishi changes his mind a lot but at the moment he says minato is the strongest dead ninja so until further notice we have to assume he is.Sandaime Raikage: received only a scar from eight tails.
Yondaime Hokage: sacrificed his life for sealing the 9 tails.
though its hachibi << kyubi, we can't really tell