Limited volume high performance flush valve assembly

A flush valve assembly for a toilet water tank, wherein said water tank stores water for delivery to a toilet bowl in fluid communication therewith, said flush valve assembly comprising:

• a body subassembly comprising a valve body having a proximate extent with a radiused inlet defined thereabout, a distal extent having an elevated base, and a coextensive wall therebetween;
• a poppet valve subassembly comprising a buoyant float means being coaxially and reciprocatingly mounted with respect to said valve body so as to create a valve opening therebetween when said float means is elevated relative to said valve body;
• said poppet valve subassembly being reciprocable between a first rest position, wherein said float means is sealingly seated proximate said radiused inlet of said valve body to obstruct fluid flow through said valve opening, and a second open position, wherein said float means is elevated relative to said radiused inlet;
• and
• guide means comprising a guide member in operative communication with said float means and alignment means to accommodate reciprocable movement of said guide member relative to said valve body, said alignment means inhibiting deviation of said guide member from a predetermined axial guide path when said float means moves between said first position and said second position,
• wherein said body subassembly further includes a valve bracket having an orifice to accommodate seating of said elevated base relative to said water tank.