dont know what the hell a donut gasket is....but if you go to autozone you can pick up either some Cork or Rubberized Gasket maker. Its a 1foot x 2foot long sheet for $6 and you can cut out and make your own gaskets.
oooh different kind of gasket then. I know what you're talkign about now. Yeah thats a donut gasket. lol i wasn't thinkin at 1st. Ok. well try modulardepot.com go to the forum section that says "ask Randy", he works for Ford and can get you the part number, part and price for what you are looking for