Just noticed the Mk. II part. That's the kit I've got. The .46 AX seems like an awfully big, heavy engine for that design. You could do it with modification, but the engines it was designed for had smaller dimensions and they were much lighter. You can get an engine comparable in weight to the old .35 to .40 size engines of the time, but with a LOT more power, by getting a modern .36 type. Jim