An engine, e.g., a cam drive, barrel-type internal combustion engine, that includes: a main drive shaft defining a longitudinal axis; a sinusoidal main drive cam rigidly attached to the main drive shaft; a plurality of cam members that are in contact with the sinusoidal main drive cam and that are configured to follow the sinusoidal main drive cam, wherein rotation of the sinusoidal main drive cam corresponds to reciprocating linear movement of each of the plurality of cam members in a direction parallel to the longitudinal axis; for each cam member, a pair of linear pistons disposed on opposite sides of the cam member for reciprocating linear movement within respective cylinder bores.