Development continued and the later Sabre VII delivered 3,500 hp (2,600 kW) with a new supercharger. The final test engines delivered 5,500 hp (4,100 kW) at 45 lb/in2 boost. By the end of World War II, there were several engines in the same power class. The Pratt & Whitney R-4360 Wasp Major four-row, 28-cylinder radial produced 3,000 hp (2,280 kW) at first and later types produced 3,800 hp (2,834 kW), but these required almost twice the displacement in order to do so, 4,360 cubic inches (71 litres).