A cutter assembly for an agricultural harvester header comprising: a knife drive that includes: a housing, a crank shaft having a first cylindrical portion and a second cylindrical portion radially offset from the first cylindrical portion, a first eccentric sheave mounted on the first cylindrical portion and a first eccentric rod extending from the first eccentric sheave, and a second eccentric sheave mounted on the second cylindrical portion and a second eccentric rod extending from the second eccentric sheave; a first cutter bar attached to a distal end of the first eccentric rod; and a second cutter bar attached to a distal end of the second eccentric rod, wherein the first and second cutter bars (102, 104) are in side by side relation and wherein rotation of the crank shaft provides linear oscillation of the first and second cutter bars (102, 104), characterized in that the knife drive further includes first and second plungers (82, 84) each having first and second ends, the first plunger supported for linear motion at a first end of the housing and the second plunger supported for linear motion at a second end of the housing opposite the first end, the first plunger being connected at the first end thereof to the second end of the first eccentric rod and the second end thereof being configured for connecting to the first cutter bar, the second plunger being connected at the first end thereof to the second end of the second eccentric rod and the second end thereof being configured for connecting to the second cutter bar, wherein rotation of the crank shaft causes rotation of the first and second cylindrical portions (66, 68) against the first and second sheaves (74, 76) and linear reciprocating motion of the first and second plungers (82, 84) in opposite directions. a knife drive that includes: a housing, a crank shaft having a first cylindrical portion and a second cylindrical portion radially offset from the first cylindrical portion, a first eccentric sheave mounted on the first cylindrical portion and a first eccentric rod extending from the first eccentric sheave, and a second eccentric sheave mounted on the second cylindrical portion and a second eccentric rod extending from the second eccentric sheave; a first cutter bar attached to a distal end of the first eccentric rod; and a second cutter bar attached to a distal end of the second eccentric rod, wherein the first and second cutter bars (102, 104) are in side by side relation and wherein rotation of the crank shaft provides linear oscillation of the first and second cutter bars (102, 104), characterized in that the knife drive further includes first and second plungers (82, 84) each having first and second ends, the first plunger supported for linear motion at a first end of the housing and the second plunger supported for linear motion at a second end of the housing opposite the first end, the first plunger being connected at the first end thereof to the second end of the first eccentric rod and the second end thereof being configured for connecting to the first cutter bar, the second plunger being connected at the first end thereof to the second end of the second eccentric rod and the second end thereof being configured for connecting to the second cutter bar, wherein rotation of the crank shaft causes rotation of the first and second cylindrical portions (66, 68) against the first and second sheaves (74, 76) and linear reciprocating motion of the first and second plungers (82, 84) in opposite directions. a housing, a crank shaft having a first cylindrical portion and a second cylindrical portion radially offset from the first cylindrical portion, a first eccentric sheave mounted on the first cylindrical portion and a first eccentric rod extending from the first eccentric sheave, and a second eccentric sheave mounted on the second cylindrical portion and a second eccentric rod extending from the second eccentric sheave; a first eccentric sheave mounted on the first cylindrical portion and a first eccentric rod extending from the first eccentric sheave, and a second eccentric sheave mounted on the second cylindrical portion and a second eccentric rod extending from the second eccentric sheave; a first cutter bar attached to a distal end of the first eccentric rod; and a second cutter bar attached to a distal end of the second eccentric rod, wherein the first and second cutter bars (102, 104) are in side by side relation and wherein rotation of the crank shaft provides linear oscillation of the first and second cutter bars (102, 104), characterized in that the knife drive further includes first and second plungers (82, 84) each having first and second ends, the first plunger supported for linear motion at a first end of the housing and the second plunger supported for linear motion at a second end of the housing opposite the first end, the first plunger being connected at the first end thereof to the second end of the first eccentric rod and the second end thereof being configured for connecting to the first cutter bar, the second plunger being connected at the first end thereof to the second end of the second eccentric rod and the second end thereof being configured for connecting to the second cutter bar, wherein rotation of the crank shaft causes rotation of the first and second cylindrical portions (66, 68) against the first and second sheaves (74, 76) and linear reciprocating motion of the first and second plungers (82, 84) in opposite directions.