On to the trans tunnel.
Most of you know Mopars are torsion bar cars. They have a torsion bar crossmember that runs from rocker to rocker. It's about an 1/8" thick and provides a lot of the bodies torsional rigidity. My car utilizes the stock floor, and is basically stock bodied except for subframe connectors and a grafted on front/rear subframe (It would have been
SOOO much easier to build a tube frame chassis and just set the body on!).
To install a T56 size transmission requires cutting a section of this crossmember out in the middle. I wanted to tie the crossmember back together with the same strength, and needed to be able to slide the largest diameter of the trans through it. I ended up building this piece after trying lots of different cardboard template:
I then realized I had a problem. I build the rear of the tunnel much earlier so I could build and install the seat structure. I kept it low because I wanted a console. When I ran the seat bar over the driveshaft, I stayed at the same height as the tunnel:
This would have been fine, except that with the motor/mid plate, I cannot tilt the engine down to remove the trans. The transmission needs to slide straight back far enough to get the input shaft out of the clutch.
After measuring how far I needed to go back, I raised the seat bar enough to allow the trans to slide through it that distance (with the shifter removed). I then had to cut back into the previous tunnel that amount and a make a removable section that could also seal off fire/smoke. The lower bolts on this panel would be inaccessible with the seats in place, so they bolt in from the underside.
With that panel done, I laid out how I wanted the tunnel.
I built the pieces that attached to the floor that also attach the removal cover for the shifter. I flanged everything as a fire stop and will seal everything with fire tape:
Then I started on the removable shifter section:
I added some baffles underneath to attach and seal the Nomex shift boot.
I made the front of the tunnel section that will connect to the firewall, but needed one more access panel to service the shift rod, reverse cable, and gear position sensor:
Not sure what the metal composition of the factory sheet metal is, but TIG welding was a no-go. Mig it is.
So this is a weird step down tunnel! My console is flush with the last step, so it transitions into the shifter panel level. The side cutout's on the shifter panel become the E-brake lever and sway bar adjuster pockets.
The drop down from the front section will probably get cup holders. This whole thing will be covered in removable upholstery.
And just because you made it this far, here's a couple of renderings of the outside. Not exact, but close enough to build panels and work from, which is what I'm doing now: