Originally Posted by 
roobar_and_custard
				 
			Having seen the picture of the 101 with its rear wheels in the air under heavy braking, I wonder why there is an expectation of extra stopping power.
Locking the front wheels is just past the point where maximum braking is achieved, which from recollection is quite possible with 101 drums.  So no matter how many callipers you fit, this maximum is unchanged.
Where you benefit with discs is:-
  1) greater capacity for heat dissipation meaning greater ability to maintain brake performance under heavy use (high speed, prolonged use, long down hills, etc...)
  2) no adjustment required meaning less time spent with wheels off the ground, spanner in hand, cursing.
  3) reduced sensitivity to coefficient of friction variation which means more even braking and less weaving
  4) similar to above, but they don't suffer from being wet too.
Now while the Zeus brakes require some adjustment to get them to fit behind 16" rims, there are plenty of calliper/disc set-ups that will fit and will be matched to the GVM needed to have some chance of engineering approval.
It's worth doing for the above reasons, but don't expect massive increases in outright stopping power.  The real gain is being able to step hard on the pedal confident that you will stop in a straight line.
Just my two pennies worth.
Ian.