While doing some research online, I saw same good pictures of the 20b installation in Tracy's RV-8.  I am particularly interested in the wedge diffuser he used for his radiator cooling.  I've been looking on the mail list, but don't see anything referencing it or any other information about the ducting.  I have been planning on using a ventral radiator with a scoop to provide the cooling I'll need.  I'm building a BD-4 and I may have enough room in my cowling for both the wedge diffuser and cooling for my oil.  Does anyone have thoughts, suggestions or directions?  I've looked for the K&W book, but haven't been able to find it or any copies of it.