I have a 2005 f250 6.0Lt Diesel with 600 horsepower.Question:  During the ZFS650 overhaul I know its going to need synchro, i think a bearing or the shafts are getting some wear, and possibly thinking about a short throw shifter during the overhaul.  Can you offer any suggestions for the increase horsepower?Answer:   We can rebuild and dyno test your ZFS650 6 Speed transmission, the transmission will be rebuilt under our part number MTFFRD076 your cost is $2526.67. plus freight and assumes your existing core case is not damaged.To accommodate the additional horsepower we would recommend that we cryogenic treat the input shaft, 5th c/s gear, 4th gear set  and 3rd gear set for a total of 39lbs at $10 per pound = $390 additional cost this will add about 30% in additional strength.We can install a short through shifter at the time of the rebuild your cost $195… just make sure you send your core with the shifter stub. You can see the other parts that we can supply for the Ford ZFS650 on our site.