Click here for the lyrics, Joe (e-mail sent)
Here's what's said about the song in Songs from the Front and Rear: Canadian Servicemen's Songs of the Second World War (Anthony Hopkins, 1979):

Sylveste is...an incredible Paul Bunyan of a man, heroic and unstoppable...
"Sylveste" proved to be a song that was, nevertheless, more known of, than known. No typescript copy of it was located; many respondents said they had often heard of it, but could not themselves sing it. One singer provided most of the lyrics here, but repeatedly claimed that he had forgotten four lines near the beginning. His brother claimed with equal vigour that the song was complete. In any case, even in the state he is here, Sylveste is more of a man than anyone could ever hope to be.
The Lusitania was a passenger liner, torpedoed by a German submarine off Iceland in 1915, with the loss of more than 1,000 lives.
Jack Johnson, a black, won the world's heavyweight boxing championship in 1910 by knocking out James Jeffries. Jack Dempsey won the heavyweight title from Jess Willard, the man who defeated Johnson in 1919, lost it to Gene Tunney in 1926.
The spoken exclamations in the song can be improvised, and more or less added whenever you think you can get away with it.

-Joe Offer-