LA engine is a non bearing ,has bushings,engine manf. by OS,ABC is a non ringed engine,an ABC engine will break in faster,but when it wears out the piston and sleave will need to be replaced,the ringed takes longer to break in but seems to handle dusty fields better,do not break them in the same,as far as which is better,an ABC or ring,I think about the same,the bushing engine is less money ,less upkeep,and less HP.
Have a goodun,John.