MKI, MkII, and MkIII Battery Box Instructions
1. Remove the original battery brace.
2. Position the battery box just to the right of the gas tank mounting brace on cars with 3 link rear suspension. Position the battery box in the center on 4 link and IRS cars. Level the side flanges on the battery box with the tops of the 3/4 inch square tubes. Drill and rivet the box to the 3/4 inch square tubes.
3. Drill and rivet the sides of the battery box.
4. Temporarily install the upper trunk floor, then reach through the hole in the bottom of the battery box and trace around the top of the box to mark the opening you will be cutting. Then remove the trunk floor from the car and cut the hole you marked.
NOTE: A good way to end up with a nice neat hole is to start with a rough hole in the center of where you want to end up then sneak up on your line with several cuts around the hole making your final cut only remove about a ¼ inch of material. Then clean up the cut with a file. It is also a good idea to do another test fit before you make your final cuts.
5. Install the trunk floor and rivet in place.
6. Install the battery and the top.
The battery you want is an Optima RedTop type 34 (not the type 24/78):