Is anybody out there using there old fords at the tractor pulls? If so what are you using. A friend of mine pulled with his NAA last week. It pulled about the same as a farmall H. He's got too much money tied up in the NAA restore and the rears aren't that strong on that model so he is looking for a 600 model to pull with. Maybe a 621 with no hydraulics and no 3pt hopefully to drop down a class. Any input might help.
tell him to save his money on the 600 series.. the naa and 600 series are so close in capacity as to be null difference.. 800 series has a beefier rear end.. weighs almos the same as the naa and 600 series.
for instance, the ring gear in the rear end of the 600 and naa are the same.. a conn4210c
the 800 has a ring gear conn4210e..
the axles on a 600 and 2120 are the same and are 312187
the axles on a 800 are the same as a 4120, industrial, and hd industrial, and are b9nn4244a
just my opinion anyway.. if you are gonna upgrade from a naa.. skip the 4cyl 6xx and 2xxx models and set into the 4cyl 8xx, 4xxx, 184x industrials... get heavier axles and rears..