The Ashtabula adapter kit is as follows:
http://harriscyclery.net/itemdetails.cfm?ID=1335

It contains the two adapter cups (and the three bolts used to secure them) that you need to install in the Ashtabula BB shell before installing the bottom bracket assembly itself. After installing the adapter cups, you will need the bottom bracket itself. The length of the spindle (determines how close or far that crankset will be to the frame) is the tricky part that I cannot answer. That said, I am pretty sure you will need a 68mm shell - the 73's are for oversized (wide) MTB bottom bracket shells:
http://bicyclewarehouse.com/itemdeta...te=google_base

Hope this helps.

-Kurt