What 2slow2matter said, but ABC= (Aluminum, Brass, Chrome). ABC, ABN engines are more forgiving for "lean/hot" runs and can suffer from a "rich" setting it can ruin the piston/liner fit, most people say ABC/N are more user friendly, I like them both, Ringed and ABC/ABN have good and bad points. Good Luck

The SX is a BB engine, LA's are plain bearing.