Mercury VIS.2 (1933) 605 hp. Mercury VIA (1928) 575 hp (became the Pegasus IU.2) Mercury VIIA 560 hp (became the Pegasus IM.2) Mercury VIII (1935) 825 hp, compression ratio 6.25:1, lightened engine. Mercury VIIIA Mercury VIII fitted with gun synchronisation gear for the Gloster Gladiator Mercury VIIIA 535 hp, second use of VIIIA designation, (became the Pegasus IU.2P) Mercury IX (1935) 825 hp, lightened engine.