Which of yesteryears iconic top of the bill clashes would have been most lucrative for the Promoters?

There were plenty of them in that 60's-80's period.However,we must take into account the seat prices rose through each decade.Also.many were oft repeated around the country.The famous Pallo/McManus bouts must have been a good earner for the Promoters.Would any other top of the bill clashes equal them.? your opinions please.