Abstract: A head assembly for a multi-cylinder compressor or pump having a first cylinder and a second cylinder includes a valve plate that has a first cylinder portion, a second cylinder portion, and a third portion positioned therebetween. The valve plate further including a valve plate face with a first aperture extending through the first cylinder portion and a second aperture extending through the second cylinder portion. The head assembly also includes a head cover having a head cover face, and at least one wall extending from one of the valve plate face and the head cover face to form a channel. The head cover being couplable to the valve plate such that the channel cooperates with the other of the valve plate face and the head cover face to form a chamber extending between and enclosing the first and second apertures of the valve plate.