Feud was once a week from September 1977 to January 1979, twice a week from January 1979 to September 1980, and five days a week until 1985.
A little quick research shows a reference in Broadcasting Magazine in the NATPE issue from 1979 that seems to indicate 98 episodes had been produced up until that point. 39 episodes for the first season (confirmed in another Broadcasting issue), the original order of 39 for the second season (again, confirmed) and 20 apparent additional episodes when the show went bi-weekly mid-year. Season 3 seems to have been 78 episodes (2x39).
That leaves 800 episodes which, divided by 5, come out to 160 a year for the five stripped seasons. 160 was a relatively common number for a 5-a-week show, and I seem to recall some of the more recent seasons of Feud had that same number of episodes.
Don\'t take any of my calculations for gospel, but they seem pretty reasonable. If anybody can prove me wrong, go for it.