We have a database for NFL and CFB that goes back to the 1978 season (in addition, I have an archive of every Super Bowl that goes all the way back)
Before that, nothing I trust.
I have found that if you search throught he Google News Archive you can find spreads of older games referenced in newspaper accounts (trick: include the word "underdog" OR "favored" in your search)
I figure there's a few degens like me who enjoy this kind of digging . . . so I'm starting this thread as the HQ for spreads to well-known games that we uncover.
Simply post the game, the spread, and a link to the source.