Yes and its possible to convert.
About 3 months after we posted a picture of our conversion MHZ came out with their protoype and ran a short run of conversions.
It may have intended to be a marine engine at some point as the cylinder is already drilled and tapped for the water jacket hold down screws.It appears Zenoah stopped short of a PUM version.(representitives from K/Z nor Husqvarna has responded to my inquires regarding the future availiblilty of PUM versions)
The water jacket is custom made as none of the previous PUM water jackets will fit, nor will any of existing motor mounts fit.
I have not set the price on a full conversion nor made plans to publicly market anything until everything has been thoroughly tested. ( A complete bolt on that would include the water jacket, a machined cylinder, motor mounts,throttle linkage, starter and the ignition trigger)
The key thing to getting these engines producing power is to have the correct expansion chamber, unfortunatly there is not one made that will work correctly with a gasoline engine of that size.It takes time to develope pipes.We wasted 18 months on existing pipes and now we are going to do our own.
The big reason you don't see a proliferation of parts for these engines is:
1 its not NAMBA legal for G-1
2 the price of the engine was too high , but it is coming down
3 its not an engine suited toward large cats or sport hydros, its better suited to small monos, think in terms of high rpm and small props
4 the rank and file have yet to see a boat powered by one of these running heat racing speeds, there is no reason to not expect this engine to be able to run mid 50s.
Keep an eye on MGB.com there may be an article on this down the road.