This summer I displayed my Farmall 400 with the 2-71 Detroit Diesel conversion at the Clarksville Steam and Gas Engine Show in Clarksville MI.  I also had opportunity to dyno it on an old M&W PTO dyno; it put out 58 hp.  They also had a non competitive tractor pull demonstration, so took the opportunity to give tractor pulling try.  Attached is a video my friend took of the pull.  It pulled down to 800-900 rpm and lost traction – Pulled in low with the TA back.  No liquid ballast in the tires.  No noticeable smoke.