Hi Greg. Sorry for the difficulty with dimensions. Australia changed to the metric system in the mid 60's, so I tend to use them most of the time, although I prefer imperial dimensions as that is what I grew up with. See changes below, imperial dimensions in brackets.

Can any one suggest a radial engine to suit a CM Pro/Hobbyking A6M Zero. It is suggested for a 40-50- CC(3.25c.i.) Gas engine. The model is 2100 w.s.(83 inch), wt.is 6.5 Kg (14.33 pounds) approx. I have had a look at the Saito 53cc (3,25 c.i.) glow 5 cylinder radial but it would be pretty tight in the cowl, which is 230 inside diameter and the Saito engine is 225 diameter, not including any onboard glow fittings or any other anclliaries. Any suggestions as to what I could use would be greatly appreciated.
Thanks, Ian