did you take any of the dimensions down? I would love to know being I have the same yr model and would love to steal this idea from you !!! That is a helluva nice box and a great job on the install!!
I started with going to the junk yard and buying a center seat for $15 (I didn’t want to mess up my seat if it didn’t work).
I unbolted the armrest from the bottom of the seat and took off the seat cover. The metal frame just slips out of the cushion.
Then I cut out all but about ¾ of an inch on the sides and top of the seat cushion from the bottom side.
I knew I needed at least .6 cubic feet for the pioneer subwoofer that I was using (the speaker range was .6 to 1.2 cubic feet).
I measured the width that I needed by measuring the distance between the arm rest hinges (13 inches) the longest length I could go without cutting the seat cover was 19 inches so the depth I needed was 8 inches to make .75 cubic feet.
I went to home depot and got a 2’x4’x3/4” MDF sheet and had them cut out the pieces (don’t forget to have the front and back pieces cut to 11.5 wide 6.5 high the total box size is 13x19x8) $11. Keep all the extra pieces you will need some of them for the cutouts on the sides.
I glued and screwed the front back and sides and just put 2 screws in the top and bottom (make sure you pre-drill all the screw holes). I used 2 1/4 inch wood screws with ¾ flat shanks so the pieces pull together correctly $3.
Place the box in the cushion and seat cover the put it in the truck to mark where you need the cutouts.
I cut 8 3”x4” blocks from the extra pieces and screwed 2 to each cutout area leaving at least ¾ inch overlap.
For the next part I used a router but I’m sure there are other ways to do it. I cut out 1.5 inches deep from the bottom of the marked areas.
Went to radio shack and got the speaker terminals $4.99. I cut that hole out with the router use silicone sealer here
Glue and screw the bottom on then glue and screw the blocks.
Bring it back out to the truck and mark the holes for mounting. I used 5/16 t-nuts for the mounts (box of 25 $6). You can drill holes for the t-nuts anywhere in the marked area on each cut out.
Cut the hole for the speaker in the center of the bottom of the box with a router if you have one it’s easier than a jig saw. Pre-drill the holes for the mounting screws.
I used some 10 gauge wire I had in the shop and got some wire ends and crimped and soldered them on the wire. I used the terminals with the hole in the middle and screwed them to the post on the terminals.
Now is a good time to seal the bottom and sides of the box with silicone $6. Make sure you wait at least 24 hours to mount the speaker after using silicone sealer the fumes will destroy speakers. So let it completely cure first.
It’s time to drill the holes for the armrest, the trick to this is the bottom of the hinge should be parallel to the bottom of the box (make sure you leave enough room for the t-nut fit from the back wall when you drill the top hole on each side). I forget the exact measurements of where the holes go. If you can’t figure it out I can pull the speaker out and measure it again.)
Now glue and screw the top of the box let it dry and seal it with silicone let it cure.
Now hookup and mount the speaker. I went to ace and got rubber ¾” weather strip (don’t get the foam it’s not as good) $4. Put the weather strip around the edge of the speaker cutout
Put the cushion in the cover and the box in the cushion. Mount the armrest to the box and install the stealth subwoofer.
I got the speaker I used from Wal-Mart for $39.
I have an extra foam cushion that I can cut out and take pictures if anyone needs me to
You should be able to build the box in a couple of hours and mount the speaker and install it the next day