Ok Chris I didn't get the casting #s off the housing but I will. however I  did take a glance at the 1950-T &amp; 1850 parts books &amp; I did see that there were several options for the 1850's axle unlike the 1950-T only one listed. Of corse the 1850 book only showed one picture but several discriptions. The picture in the 1950-T book of the axle is what is on this 1850 FWA. Correct me If I am wrong but 1950-T's have a bigger rear end, bull gears,&amp; axles compaired to what a regular 1850 would have. kind of like going from a 770 to a 880 rear end. I know that a 1850 front half will bolt to a 1950-T rear end as how many times has that been done over the years because of failed 310 motors. But like I  said This tractor looks to be all orignal. If this was a factory option to have the larger rear end it seems odd that its a 1967  &amp; the T's did not come out untill 68. What do you think??  I will get those #s to you soon too. Thanks Much Steve