There is plenty of room under the seat for your tunnel. The '53 and '54 Chevies were almost identical. Here is a picture of a '53 Chevy front seat out of the car. This was a 150, but the 210 used the same seats with different fabric packages. As you can see, there is about 4" of space under the seat.
The rear seat is another matter, it has a cut out in the middle to accomodate the tunnel. That seat frame will need to be changed, but it's a pretty simple fix. Here is a picture of the bare frame and the covered frame of the rear seat.
No one lives forever, the trick is creating something that will.
Last edited by DanTwoLakes; 03-04-2011 at 10:58 AM.