After a few google searches, I haven't been able to locate anything that points to him actually saying this. Most of the links that appear seem to be conspiracy-esque sites.
The quote in question:
"It is well enough that people of the nation do not understand our banking and monetary system, for if they did, I believe there would be a revolution before tomorrow morning."
That particular quote first appeared in The American Mercury in 1957 in an article How Internationalists Gain Power, and it is important to remember that the entire passage is prefaced with "It was Henry Ford, Sr. who said in substance" (emphasis mine) - that is, the quote was abridged or paraphrased - the quote also appeared in The Federal Reserve Hoax by Wickliffe B. Vennard in 1959.
So...Ford probably didn't say exactly that quote; if he did he was probably talking about "sound money." In his book My Life and Work 179:
The people are naturally conservative. They are more conservative than the financiers. Those who believe that the people are so easily led that they would permit the printing presses to run off money like milk tickets do not understand them. It is the innate conservation of the people that has kept our money good in spite of the fantastic tricks which financiers play-and which they cover up with high technical terms.
The people are on the side of sound money. They are so unalterably on the side of sound money that it is a serious question how they would regard the system under which they live, if they once knew what the initiate can do with it.
In context, this is from before the Great Depression - and in that period in American economic history after the introduction of the greenbacks but before the complete abandonment of the gold standard. There are plenty of goldbugs still on the far right in the United States.