As the Iron get set to take on the league leaders at Upton Park on Wednesday, Allardyce spoke of how much he reveres his Red Devils counterpart Sir Alex Ferguson for the achievements he has made at the club over the past two decades.
"I think you have to say the United team is as good as it has ever been because nobody normally wins the title so easily and by so big a margin, or has this much of a margin at this stage of the season," he said.
"It is pretty scary what total they might actually finish with.
"Manchester United have been outstanding and their squad rotation has been Sir Alex's masterpiece as usual, about playing the right team at the right time.
"They have not had the normal focus on three or four competitions almost to the end, the focus has come on the Premier League and they have just breezed it.
"They have just gone 'bang' and everyone else can't get near them."