I was told the 4.9 was meant to be an upgrade to the Mosquito using the latest (at the time- I believe MkIII? I have one of their "A" brochures and the 4.9/5.7 brochure around here somewhere!) "A" technology-
Kirt
Kirt Taipan 4.9 USA 159, Flyer USA 185 Will sail for food...