With the cab wider than the donor Grand Cherokee floor, I thought it was necessary to extend the front seat mount support across to the sill support like it used to on the donor.
But rather than do it on top of the floor, I thought it would look and function better under the floor instead. So I made this short centre support to go from the sill and then over lap the end of the seat support on top. The thinner part of the support is what is over lapping the one above it.
Now on to the end of the cab. The donor floor had this arrangement to strengthen the rear of the front seat mount. It used to tie in with the sill support on the end which is what the tags did. There was also the floor rail that went over that hump in the middle.
Rather than just extend from the end of the reinforcement to the sill, thought it would be stronger to cut it away and make a new one from scratch. I cut it away until the vertical part of the floor where it is the strongest. Was as far as I could go without interfering with the fuel tank which rests against the floor in the raised section.
Used the same technique as before, but just with wider flanges. I made the whole piece wider than the one I removed so it would meet where the donor floor had an overlap joint.
Can see the seat mount right next to the raised section of the support giving it greater strength. I left as much as I could of the original reinforcement it was welded too, so it now has three layers of steel above it.
The pocket you see at the end of the sill support is the bottom of the B pillar and what I made into the rear body mount. This new support should help with that as well.
So this I think should be adequate for supporting the longer and wider floor. At the top left of the photo, where the rear support is in the middle of the transmission tunnel, you can see what was the outer mount for the fuel tank. That is now mounted off a chassis cross member and I will use this mount now as an additional body mount in the middle of the rear part of the cab.