If I tell you his name is Svend Karlsen, you still don't belive me?
There is a video of Svend pulling a triple, with fairly good speed though, at 814 lbs (370 kg)
So I have a hard time believing Svend could do 5 reps with over 400 kgs (891 lbs to be exact).
For the record, I consider Svend Karlsen to be one of the best deadlifters among the strongman competitors, and also a helluva nice bloke.
YIP
Zack