Steiner's Tractor Parts is a good place to look, very quick delivery on the parts I ordered.
http://antique-tractor-parts.steine...ferguson&isort=globalpop&method=and&view=grid
On some parts you may have to go to the tractor salvage yards and search.
http://www.oldfergusontractors.com/Ferguson_Resources.htm
Good luck on the rebuild! Pics of the rebuild would be GREAT!! It will help others rebuild / restore their tractors!! :thThumbsU