the es displaced . all es engines were sohc 12-valve engines. the es1 used dual sidedraft carburetors to produce @ 5500 rpm and @ 4000 rpm. the es2 replaced this with a standard 3 barrel carburetor for @ 5800 rpm and @ 3500 rpm. finally, the es3 used pgm-fi for @ 5800 rpm and @ 2500 rpm.