Is a 91 through 95 Ford Explorer engines the same?

According to what I've read ( no )

The 1991 to 1994 Ford Explorer uses the same engine block

The 1995 and 1996 Ford Explorer uses a different engine block

The 1997 to 2000 Ford Explorer uses a different engine block again

When it comes to the 4.0 liter OHV engine

P.S. I'm not a mechanic / technician