Does anyone know what's involved in a MGB -> MGD conversion?

[SPG@ALPHA.SUNQUEST.COM (Steve Gibbons)]

Picture this:

Take your cute little rag-topped roadster.
Drop a Chevy small-block V8 (aluminum) under the hood 
        (loosing appx 80 kilos)
        (appx doubling your horsepower)
Call it a "D" (vs. a "B" or a "C")

I think a few (6 or so) prototypes were constructed.  What would be involved in
an after-market conversion?  (In really simple words for a non-mechanical type.)

--
Steve (SPG6) spg@sunquest.com