Welcome to lesson two of "Making More Storage." Regardless of whether you need storage for condiments or a good place to stash something, all speedster owners need more storage.
In this segment, Mike decides that the speedster is running great and he better clean up some of the ahem, experimental wiring that took place during the installation of the Speeduino fuel injection and electronic ignition project.
The goal was to move the Speeduino ECU to a more accessible place that didn't displace things I like to keep behind or under the seats. I started fooling around with electronics at age 5 and didn't get around to cars until I was 16, so having quick and easy access to the engine computer would mean more fun for me. I suspected that others might not have the same specific goal, but that they might want a little bit of secure storage. Here's what I did.
My car is a 1979 California Intermeccanica speedster build on a 1969 IRS pan. Your mileage may vary, but I noticed that there was a nice empty spot under the rear package tray. I liked the driver side because it was closer to where I put my wiring harness from the front dash and to where I put my rear relay and fuses box. It probably would work for the passenger side.
The plan: make a small storage box that is attached under the package tray and cut a lidded opening under the package tray carpet for periodic access.
After measuring the driver side space, I decided the box would be around 9" x 5.25" x 3". Turns out an old cardboard box for nitrile gloves is about the right size. I took an old box, wrapped it fully in packing tape, greased it down with regular bearing grease and put it on a taped down section of waxed paper. I painted it with fiberglass resin and puddled a 1" margin along the long sides. I followed with 3 layers of fiberglass and resin and cleaned it up with a final coat of just resin.
I lifted the box off of the wax paper, pulled out the box from the inside and cleaned up the edges with an angle grinder and then I sprayed it off with brake cleaner. After everything dried, I shot it with a couple of coats of satin black paint and made a paper template of the shape of the top.
Black painted box with Speeduino inside and paper template 
The package tray
Package tray carpet
The target corner drawn using the paper template, a box cutter and a sharpie.
The hole cut. Save the cutout piece to make the lid.
View from under the car with 4 mounting holes drilled.
Test fit
Lid stop and wiring grommet installed, lid leaned back.
View of lid and piano hinge - Cool little hidden storage box
Carpet back down and package tray cushion in place
Some warnings: for goodness sakes, don't hide your bitcoin fortune in here and post it on the interwebs. And remember, I'm a pro at trying out crazy ideas and only sharing the ones that work. Only try this at home, never in a verified ISO 9000 qualified facility. Only store condiments like catsup or mustard. Mayonnaise is not an approved condiment for this storage unit.
Cheers.
