The old 6's were good motors. Just about any parts, including floor pans should be available. I would suggest trying to find an older chilton's on ebay. The old manuals like chilton's covered american cars and a 7 year span. All in the same manual would be Ford, Chrysler, GM,AMC,Jeep and VW and have alot of good info. If you need some specs before you find one, I can look it up for you.
BTW, some pics???
Rock Auto is supposed to be a good place for older parts online. I've never dealt with them, but have heard good things.
Auto Parts Fast at RockAuto