I'd venture a guess that is a 1980's Speedex 1630. I have a 1632 and aside from the taller front wheels on mine, you have a large frame Speedex. If you have any tools and know how to use them, that tractor will run forever. I've modified mine somewhat, but I can attest to the simplicity and durability of these tractors. That, and I just like working on them.
See my 1632 versus my WH 310-8. I'm really anxious for some snow so I can test out my hillbilly engineering. :)
Check out the attachments and let me know what you think.