remanufactured engines are $30,000 +.
As you undoubtedly read on
http://www.superskyrocket.com the military version of the Skymaster was ferried across the Pacific to VietNam. I think they left with full military radios, which were relatively heavy compared to modern avionics.
The 3 bladed prop, Herb Harney has, improves acceleration and climb, significantly. I would suspect that you would want a Skymaster without De-Ice, because that does tend to slow down the airplane.