I don't believe there would be any difference in floor pattern from 1997 to 2008 (and then maybe not even to present, but there are no Chinooks that new anyway). Chinook used the stock Ford seat bases for their Flexsteel seats, btw.
There *might* be a difference in the area under the driver's seat due to power seat or no power seat, or due to airbag module that may have come in for later models. But I presume any of us here would modify accordingly (this would all be under the driver's seat AFAIK).
Now I'm soooo curious!
My Chinook
Re: My Chinook
1999 Concourse
