Was there a problem with stalling on 737 jets before the 737 Max, if not then why is MCAS needed on the 737 Max 8.If it was a problem why did Boeing wait so long.
Was there a problem with stalling on 737 jets before the 737 Max,
The flight characteristics, including high angle of attack operations, of the previous models of the 737 did not warrant the kind of action the MCAS system provides.
why is MCAS needed on the 737 Max 8
The Max 8 engines are physically bigger—69.4 inches fan diameter versus 61.0—heavier, mounted farther forward and higher than previously. This changed the thrust line and flight characteristics. MCAS is used to restore "normal" 737 flight characteristics.
See http://www.b737.org.uk/737maxdiffs.htm for details.