I spent the last 2 days building a crate for my 70 Roadrunner bench seat, soon to be Tbone's seat.
About $120 in materials, with some left over plywood from the sheets I bought, but I got really close to what I needed, and the 4x8 sheets were only $14 each.
Wrapped in industrial strength plastic wrap and sizing up the rest of the crate. If you'll notice the gap between the REAR seat mounts and the bottom of the crate (bottom is vertical in this picture) I took up that space with a 2x4 screwed into the bottom of the crate, running the width of the seat, and placed under the rear seat mounts. I encased the 4 seat mount bolts w/nuts attached in some spare styrofoam blocks I had, and taped and wrapped the styrofoam in place.

Here are some more pix:
Bubble wrap to take up the little bit of space here and there. The seat fits pretty tight everywhere, but the bubble wrap will keep it from moving around at all.

Everywhere there are screws going through the plywood there are wooden strips for added strength and as a mounting point. The pink highlighted area is where the screws go that hold the hinged sheet of plywood closed.

The two strips of wood across the top are so the top of the large sheet of plywood that hinges closed has reinforcement for the screws that hold the top closed. The bottom of the hinged sheet is attached by 4 heavy duty hinges, and all of the hinge screws go through both the plywood and the reinforcing wood strips the full length of those edges.

Rope handles and sawed off the excess plywood of the hinged sheet and it's ready to ship!
