You would need a net gain of 25 seats for the Dems, right? When's the last time either party saw a net gain of 25 seats or more in a presidential election year? 1980?
But Democrats are coming from a pretty low floor this time.
In 2004, Republicans gained three.
In 1996, Democrats gained nine.
In 1984, Republicans gained fourteen
In 1972, Republicans gained twelve
In 1964, Democrats gained 38
In 1956, Republicans lost two
In 1948, Democrats gained 75
In 1944, Democrats gained 20
In 1940, Democrats gained five
In 1936, Democrats gained 12
In 1916, Democrats lost 16
In 1904, Republicans gained 44
The average going back to that date is a gain of 18 seats, so that would leave Republicans with a 224-211 majority.