October 2009 tip from Rick Botting -  
There is a complete AC kit made in Italy by the firm I visited in Italy last year. He makes a new right side dash, all the plumbing, a new bell housing to drive the compressor etc. I will look up his contact information and post it this afternoon,  Rick

The company that makes the AC kit is " Autocostruzioni SD " and the owners name is Salvatore Diomante. He doesn't speak English but his daughter who works there does.  Their phone # 01-39- fax # 011.680.13.00  email  autocostruzionisd@tiscali.it     He was a wonderful resource for fabricating Miura parts. He seems to be able to make anything;  windshield trim, complete aluminum bonnets (he had 3 old ones laying outside), and he found me other unobtanium stuff I was looking for.    Rick 

good link for 400GT  air conditioning -  http://www.400gt.com/estes/AC_400GT/ac_instructions.htm