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The Shadowfast super car project

Interior concept sketches

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This page last updated on or about 5-22-08
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BACK to Me and my Shadow supercar: Project notes 1969 Ford Mustang Mach 1 supercar site map

I decided early on I wanted Shadowfast to be a two-seater, like a Corvette, various Jaguars and Ferraris, and other sports cars of the time. I purposely wanted to restrict the number of people I could carry with me, for a variety of reasons (for one thing, lots of folks were always wanting to bum a ride back then). But partly I knew that would limit how much weight we were carrying around at any given moment-- and so give me a slight performance advantage over some cars and drivers.

I also thought I could make more efficient use of the space than Ford had with their cramped jump seats in the back.

I was strongly motivated to re-do the interior partly because it was well ruined when I purchased the car. The original buyer had gotten a white interior from the factory (a major mistake!), then after that various horrendous events had occurred to forever stain that white interior to a weird, sickly looking off-white slime look. Which couldn't be improved no matter what I did to it. Yuck!

I never got to see first-hand the fold-down rear seats/shelves of some Mustangs of the era, during my ownership of Shadow. But I did get to see the two-seater interiors on some Corvettes and an AMC AMX.

View of unfolded rear seat in a 1969 or 1970 Ford Mustang
You in the 21st century though (unlike me in the 1970s) can see those factory designs.

At left can be seen the UN-folded mode of a 1969-1970 folding rear seat in a fastback Mustang.

Below at right can be seen the folded mode of a 1969-1970 folding rear seat in a fastback Mustang.

I must admit it looks nice. But I guarantee you Shadowfast's custom design was much lighter in weight, more comfortable, more versatile, and roomier and more efficient to boot.

The proof of weight difference comes from official Texas sourced documents seen elsewhere on this site, plus anyone knowledgable about the heavy steel bulkheads used in Ford's design (all of those were cast off in Shadow's build).

My custom shelf boasted deep shag carpeting, which was definitely more luxurious than the close-cropped stuff seen in the pic of the Ford version.

I certainly was able to carry more people with my shelf than I ever could with Ford's seat design (and still have tons of storage space underneath). And even pitting shelf-against-folded down seat, Shadow was still roomier. Because I did away with the squared-off side interior panels which wasted so much space, and utilized just a piece of sheet metal and layer of carpet between interior and trunk, where Ford's design obviously includes a much thicker metal bulkhead, and an extraneous layer of hard plastic shell to match the other interior panels.

And to top it all off, my shelf design rear interior could literally be removed from the car in something like ten minutes for race prep or access to things underneath for repairs or other duties. And my heavy duty plywood shelf and related inclined front panel could be used for improvised ramps or mufflers or other things in a pinch (as described in Over the edge). Ford's stock designs could never have matched all that.

View of folded rear seat in a 1969 or 1970 Ford Mustang

Rear interior of an AMC Javelin AMX
At left can be seen the rear interior of a AMC AMX. Those cars were actually shortened at the factory, leaving so little space they couldn't have sported a back seat if they wanted to. That also meant there wasn't much space back there to do anything else with afterwards, either.

Shadow's own rear shelf would be much more spacious and useful than this. But basically just a much roomier version of the AMX interior. Shadow's speakers too would be mounted in the rearmost near vertical panel (so that the rear of the speakers actually hung suspended inside the trunk).

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The old sketch at right shows the gist of what I had to work with, after the original interior components (including some heavy metal bulkhead-like stuff behind the rear seats which separated passenger compartment from trunk) were all removed.

The new trunk separator became a rectangle of thin sheet metal, covered with black shag carpet on the passenger side.

There's a few extra lines in the sketch where I was trying out some possible new interior shape ideas.

The ducting hoses from the rear brake scoops into the rear wheel wells are visible here.

A raw view of the rear interior of a 1969 Ford Mustang

A possible fully carpeted view of a 1969 Ford Mustang rear interior
Another look at Shadow's rear insides sans the factory interior. Here it appears I may be contemplating just carpeting the whole space, rather than doing anything more complex, design-wise.

The small note about letting my carpet layer act as a fabric hinge on my shelf access doors also indicates I was hoping to reduce my workload (and expenses) at that moment. I believe I ended up using real metal hinges for the doors, though.

Interesting side-note here: At some point later my friend Steve would buy a 1970 Mustang and customize it significantly himself. 1970 Mustangs were virtually identical overall in many respects to 1969s, design-wise. Maybe 95% of their parts were interchangable. For instance, I swapped out Shadow's 1969 quad headlight system cornerposts for the twins off a 1970. Anyway, for his rear interior Steve basically removed the same bulkhead items I did, and then carpeted the entire space in black shag, so that all the floor space ended up being contoured like in the image above. However, he didn't stop there. He also re-installed his black rear seats, only now with the top cushions widely separated from the bottom. That is, the bottom half of the seat went back to approximately its original position (only now atop the shag carpeting), but the top portion (the seat back) got moved to be attached to the new wall between interior and trunk. That allowed for people to lay back there to watch a movie at the drive-in with a built-in cushion for their head (I'm pretty sure my shag carpeted flat shelf was much more comfortable, though). Steve also kept the black plastic side panels for his interior, so his wheel wells weren't visible.

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Early rear interior shelf view for a 1969 Ford Mustang
To left can be seen an early shelf concept, complete with access doors for storage. Note the substantial storage space implied beneath the shelf. In this pic I'm showing the wheel well shapes exposed but perhaps covered with some sort of cloth or vinyl.

This would end up being close to the final configuration-- albeit with the roll cage also present, and the wheel wells covered with thin, flexible wooden panels.

I believe the odd texture on some interior surfaces here is meant to represent the black crushed velvet look I would eventually line some panels with.

At right can seen another version of this design, including an idea for custom door panels too.

Here I've also raised the central console for some reason (perhaps to build in a storage compartment there).

Note the wheel wells now covered by paneling.

A custom concept sketch for a 1969 Ford Mustang rear interior and door

The above graphics were apparently done before I had my roll cage in place, or had finalized the location of my automotive battery. I first tried moving the battery to the trunk from the engine compartment, like was done with Boss 429 Mustangs and perhaps other high performance models. But the trunk location gave me problems. Especially when I drastically shrunk the trunk by expanding the interior space into maybe half the volume the trunk had possessed from the factory. AND wanted to build up and maintain a virtual mobile workshop and spare parts shop in that same trunk as well. Not to mention the space needed for any road war gadgets...Ha, ha.

I ended up moving the battery to sit underneath the interior shelf, behind the passenger seat. That also meant the access doors cut into the shelf ended up being different from the sketch seen above.

To right can be seen another view of the 'raw' interior, this time with most of the roll cage included. However, it's obvious to me this sketch was done before I'd even begun actually installing the cage-- because of the fanciful curves in the bars. It's as if I thought I could bow the bars that way to better protect the curved roof (and maybe even the sides of the car too) from getting even slightly crumpled in a roll-over. In actuality it was plenty difficult enough just to get the main "L" shape bends in the corners of the main upside down "U" shape. All the actual bars would end up being straight but for the two upper corners of the main hoop.
A concept sketch of a 1969 Ford Mustang rear interior including roll bar

To right is a rough draft I threw together in 2006 of the basic final version of Shadow's rear interior as best I can recall decades after the fact.

Flexible and thin wooden paneling was used for the side walls, and covered with black crushed velvet. Strong plywood panels were used for the shelf and inclined panel at its front. Another piece of this plywood sat between the flat shelf and the driveshaft hump, underneath the shelf, for added support (that element is not visible in the sketch).


(W) window glass
(CV) a thin, flexible wooden panel with a thin fabric covering of black crushed velvet
(SC) black shag carpeting, maybe an inch deep
(S) stereo speaker
(R) AM/FM radio

A labeled chart of the final rear interior shelf design for a 1969 Ford Mustang

This configuration hid the wheel wells, but provided quick access to them, as the thin flexible panels could be removed in seconds. I don't think they needed any fasteners like screws because I cut them to fit snugly into various metal edges handy from the factory in the car. I cut the panels just slightly too large so you had to flex them to put them in place, and so could simply flex them again for removal. UPDATE: Upon further reflection I seem to remember needing to use a single screw in each of two of the four flexible panels in this part of the car, in a particular spot: near the rear corner of the small quarter window. For otherwise there'd be a gap there too large for my tastes. END UPDATE.

Of course the roll cage made some spots in the arrangements more complicated. But recall the design had no need to be as close-fitting as factory parts. Indeed, I found the two largest gaps in the design quite handy. Those gaps were to be found just behind the main roll cage vertical bars, ahead of the frontmost crushed velvet panels, and to the side of the front corners of the flat plywood shelf. Basically the gaps there were holes a bit larger than a paperback book. They weren't very noticeable though, due to their out-of-the-way location (behind the roll bars). Too, I stapled small scraps of crushed velvet cloth to the bottom edges of those flexible panels which extended over that space, so the cloth could hang below the panels and help hide the holes that way. Despite their stealth, I ended up using the holes more often to dump stuff underneath the shelf than I did the actual doors built into the shelf.

I had two other stealthy insertion points for the storage space under the shelf: gaps between the bottom of the inclined front panel and the vertical roll bar on either side of the car. I'd left loose triangular flaps of surplus shag carpeting at the ends of the inclined shelf which naturally hung over the gaps, completely hiding them, and normally looking quite solid when viewed. But you could simply push stuff through the hanging flaps and into the storage space in a split-second. Those gaps were mainly just accessible when their particular car door was also open, though.

There were three main, or formal, access hatches or panels to getting under the shelf. Doors cut out of the plywood itself. They too were carpeted, and when closed you usually couldn't tell they were there at all except by their telltale handles or knobs. The standalone door behind the driver's seat had a round knob nestled in the shag, while the double doors over the battery behind the passenger seat had wedge shaped pulls more like drawer handles.

The single extra long battery cable ran to the engine compartment along the bottom edge of the passenger side door. Apparently that was a fairly protected spot there because the cable never got cut despite some major damage happening on that side of the car (I guess the diagonal roll cage bar in that spot helped that some too, now that I think about it. Hey! I never realized that before now!). IMPORTANT NOTE: If you have your battery this far from your motor, you MUST use the highest quality battery cable you can get. For the longer the cable, the more power loss. Too, the lower quality the cable, the more power loss. I ended up getting BOTH an extra high quality cable AND extra strong battery. END NOTE.

SIDE NOTE. Having your battery mounted amidships like this often comes in handy for things like boosting other folks off. For you don't have to be nose to nose. Just attach through an open window. END NOTE.

I believe I cut the main flat plywood panel narrow enough so the main angled roll bar supports required no notches be cut in the wood's rear edges to accomodate them. But my memory's fuzzy on this point. Another hard to recall item involves the radio mounted over the hump in the inclined panel. I know for sure I had an AM/FM radio mounted there at some point. But I may have mounted a tape player there too along the way-- or replaced the Ford AM/FM radio with one which included a built-in tape player. Like I say, it's difficult to recall that particular detail now. The tape player issue is also tangled up with the fact for a while I mounted a tape player in the center of the original Ford dashboard. I'd eventually replace the entire factory dash with a custom one, but it took me several tries before I was satisfied with the results. So Shadow's dash switched back and forth a few times between factory and custom, there. Ergo, any tape player location also changed a lot.

I don't know if it shows in the artwork, but Shadow's carpeted rear shelf was quite comfortable, and could sleep two fairly well with the front seats folded forward. The shelf and incline panels were also very strong, maybe made of some of the sturdiest and thickest plywood widely available at the time. Such panels can be very handy indeed under certain circumstances.

The inclined shelf didn't rub up against the backs of the front seats. There was a healthy gap there where I often stashed stuff like tapes and drinks and more for convenience. I think I recall at minimum a six inch gap there even when both seats were adjusted as far back as they'd go with factory specs.

The roll cage itself got covered in a battleship gray colored foam rubber, meant to be pipe insulation, but also good and spongey to protect noggins from contact with metal pipes. I slit the insulation for an easy install, then just wrapped it with duct tape in a few spots. The insulation was shaped to fit and so didn't need much help hanging on the bars like I wanted.

The true source of this page is

1971 Boss 351 Mustang black leather front seats

1971 Boss 351 Mustang black leather front seats

Not shown in the above image are at least four roll cage components: The larger diameter pipe sleeves on the driver's side (the sleeves are reinforcements for the base of the main roll bar frame), the two welded tie-ins between the roof frame and the main roll bar corners, and the 45 degree angled bar which ran across the passenger side doorway between the upright and the floorboard.

Also not shown is the rear end of the overhead console plate, which basically consisted of a thin flat metal length welded atop the center of the main roll bar at rear, and to the roof frame above the windshield at front. This particular element wasn't meant to strengthen the car, but merely provide a rigid spot to which to attach overhead console elements like a CB radio and other items. I had to use a torch to cut a notch from one side of the long plate near the front so the rear of the CB radio could tilt upwards past it, and swivel for use by both driver and passenger as I wanted. The torch was also used to cut a hole in the center of the plate not far from the roll bar, so my radio cable could connect to my CB antenna which was mounted in the center of the car's roof (Wow! I only just recalled that particular bit of torch use as I typed it up!).

To left can be seen what Shadow's supercar driver and passenger side seats looked like. They were black leather, and came from my friend Steve's wrecked 1971 Boss 351, if I recollect correctly. I used them to replace the original white buckets the car came with.

It's been tough to find images of these seats: apparently they were extra cost options or something. For virtually all the 1971 Bosses (or claimed Bosses) I found online in 2007 sported seats more like plain Mach Ones or others of the time.

Again-- if memory serves-- it wasn't difficult to install these 1971 seats into my 1969. At most I may have had to switch some metal framework from the bottom of the 1969 seats to the 1971s, so I could bolt them in properly.

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