Busone, what kind od setup do you have to get 13 mpg? Is your powertrain stock or have you made a few mods?
Wolfman, I can get a rebuilt pumpkin from the International dealer for $1400.00 plus 4 hours of labor at $85/hour. That may be cheaper then the OD unit and modding the drive shaft.
My thoughts are, it takes horsepower to climb mountains, and with 210 hp, I'm only going to get 30 to 35 mph on a long 6 percent grade, be it in 2nd, 3rd, or 4th gear, depending on the axle ratio. Therefore I may as well cruise the flats at a comfortable ( and quiet ) RPM, plus get the extra MPG bonus by not taching out my engine. Perhalps a 3:42 ratio may cause too much strain. I may re-consider a 3:70 ratio, which may give me the best of both worlds. I will admit, the 4:44 ratio is great for city stop and go traffic, but I plan to cruise the big roads. What say Ye?