Type 4?

[Jeza]

If your not so keen on the fabrication and on a budget, check out Sharpbuilt from Australia.

They offer fiberglass cylinder covers that you use with a standard dog house fan shroud, to convert the engine to upright cooling.
http://www.sharpbuilt.com.au/new_page_2.htm

The Joe Cali book also talks about clutch and flywheel options, but I can't remember the details for a non-IRS bug.

Cheers
Jeremy