CEV,
Before you go to a Perry pump I suggest you check a couple of things: use a good plug - OS A5, or a No.8; make sure the tank outlet is is positioned level with the carb spray bar. Also use 15% nitro if you can. A mouse can muffler is fine for a Funfly but for a Pattern Plane like a Wide Body 60 you might do better with a Macs Muffler (the OS 61FX fits the 91). Better still go with an "S" header (manifold) and a Hatori type pipe from Just Engines in the UK. But check the tank position first.
Saludos