Our flat pitman is the stock 85-97 F350 4x4 pitman arm. It is longer than all the other OBS pitman arms and is necessary to get full turning radius from the Dana 60 axle.
When swapping a Dana 60 this is necessary, this is also the pitman used in crossover steering kits with less than 8" lift.
CHOOSE STOCK APPLICATION FOR OPTIONAL REAMING UNLESS YOU'RE SWAPPING IN A 05+ COIL SPRING AXLE OR USING GM TIE ROD END
-F-350, factory Dana 60 axle
  If you're installing the 3 inch reversal using stock worn out springs, we don't feel its necessary. The reason is, your not gaining 3 inch's of lift over stock, your compensation for old springs, probably only gaining 1.5 -2 inch of lift, some times less.
-F-250 installing a reversal and Dana 60 80-97 axle
  The f-250 has a shorter throw than the F-350, so to get full turning radius you need to either swap on the Factory F-350 arm or our drop arm. The determining factor is if you are using new F-350 springs, or refreshed as some springs shops term it, you should use the drop arm, which is only actually 2 inch's of drop over the f-250 arm, but longer to allow full steering. If using worn out springs, then switch to a stock F-350 arm.
-5 inch Shackle reversal under anything
   Yes, its a 5 inch lift, and if your adding it to other springs you need either our Ball Joint 60 crossover kit, or a king pin 60 cross over steering kit depending on donor axle, not just a pitman arm.