$55K in 1975 was the equivalent of $254,000 today. http://www.usinflationcalculator.com/
Not sure what to make of it. It's likely Wu Ngan would have been an heir to Lee's estate and received at least some money. But why he was given this large amount in the form of a 'loan' is anyone's guess. The loan even had an interest rate of 8%, which was 2% higher than the US prime rate at the time.
Wu Ngan's letter acknowledging the debt owed is dated July 21, 1975. This is right in the middle of the dispute between Linda and Raymond Chow. According to Tom Bleecker's book, on August 6, Chow made a final offer to Linda to settle what is owed to her: $2.4 million. Adrian Marshall counters at $2.7 million.
Anyway, given the timing, it's possible Linda was 'hiding' the money with Wu Ngan, maybe for tax purposes. Or maybe it was triad money Golden Harvest or Bruce had accumulated and that Linda wanted to hide. Lots of possibilities. If it was hush money I doubt it would be in the form of an official loan.
The loan to Bob Baker ($10,000) was in Hong Kong dollars. Baker acknowledged receipt on Jan.7, 1974. This was not not very much money, about US $240.00 dollars back then, and today about US $1,275.00. It almost sounds like the cost of a plane ticket. Maybe Bob was just really broke and needed to borrow some money.