If we are talking about where things are made, it should be known that cummins blocks (at least the pre-2003 5.9) were cast in Brazil(dreaded 53 blocks

) and Mexico.
All the B blocks are cast in Brazil and Mexico, been that way for many years. The B fuel pumps come from India, not sure where the turbos are made lately (although I can check when I get to the office if it really matters)
For what it is worth, a stock 3.9 with tweaked fuel pump, 6B marine damper, GM 12-bolt rear and a BW T-5 in a '54 AD pulled a 6000# horse trailer all around the US racking up about 250,000 miles while getting good fuel economy, and cruising at 70mph. Estimated 180hp (it never made it on the dyno). The trans was the weak link, however lived with proper driving
Scott