Adding a Dash Crash Rail Assembly
to a Metal Dash Conversion
- Tom Rynne

As of:  17 April  2006 

        I'm in the process of building a V6 powered MGB using a 3.4L V6 from a Camaro as well as a T5 tranny from the same year 94 Camaro.  One aspect of this build has been to produce a custom dashboard.  To accomplish a more "retro" look I have chosen to use the metal dash backer from the pillow dash used on B's from '68 to '71.
        Some of you may have seen similar conversions using this backer and all I have seen allowed the tops of the mounting studs to show thus having a row of what look like large rivets running across the top of the dash.  I wanted both a more finished look as well as a look more like the early metal dashes which have a padded rail across the top of the dash which blends in nicely with the door cappings and rear surround as they are all vinyl on older cars.
Here's what I did :
        I used 1/8 inch plywood for both the backer and the "brow" of the pad I constructed.  I had this on hand from another project, and I bought it from Aircraft Spruce ( ).  This was a 2 foot by 4 foot piece and was expensive to ship.  The same stuff is available in large craft stores and/or marine supply houses.  A couple of 2x2 sheets would work but would mean you'd have a seam in the middle of the pad which probably isn't a big deal since this whole thing gets fiber glassed.  Foam board available at hobby shops would also probably work.  It's a paper faced foam sandwich.
        I started out by bolting on the stripped and primed steel backer to the car and putting beneath it a strip of polyethylene sheeting which covers the top of the dash and hung down into the car.  The plastic will allow you to epoxy glue and fiberglass the pad while on the car and not gob up everything with resin.  You also want to make sure the dash has the screws fitted to the mating holding brackets so the dash will have the same fit and curvature it will when finally mounted on the car.
        The first step to making the dash backer is to make a pattern using ordinary corrugated cardboard.  You need a strip about 6-8 inches wide and 4-5 feet long.  Holding this in position and bending it to the contour of the area where the rivet heads show you use a pencil or marker to trace both the top and bottom curves where the pad will fit.  This doesn't need to be totally exact and using it to cut the plywood it is always better to cut a bit larger and sand or trim for the final fit.  What you end up with is a long strip which is about an inch wide and has a gentle curve from one side to the other.
        Now use a scissors or razor knife to cut his out and match it up to the dash by taping it down a few places and trim as necessary.
        Next you want to transfer this pattern onto the plywood.  This is more easily accomplished if you use masking tape every 6-8 inches to hold the pattern down on the plywood for tracing, otherwise the cardboard will tend to flex as you try to draw around it.  You can fill in the pencil lines once you get the pattern traced between the tape strips and the pattern off the plywood.
        Now use a saber saw with a fine cut wood blade and cut out the backer, again erring to the big side and then trim and sand as needed.
        Mount the wood strip to the dash with masking tape strips and look and mark where it needs trimming and sanding.  Take it of and sand the edges.  I used a belt sander clamped to a table and used the front roller like a drum sander to get a closer shape.  It is important that the top edge comes even with the dash top and doesn't stick above it because we will be adding a top to this again cut from plywood.  This takes a bit of trial and error and if you sand it a bit too much it's no big deal since the glue and fiberglass is going to fill in.
        The way I wanted this pad to work is that I wanted it completely separate from the dash and not glued to it.  For this design I needed to have a way to bolt it onto the dash from behind after the dash is mounted. 
To do this I used what are known as weld nuts.  These look like a little top hat, having a metal flange and a tubular section sticking out of it which has threads inside of it.  I used 3 of these with 1/4-20 threads.

        I placed my backer onto the dash, again holding with tape and located where the mounting bolts would fit. I chose two locations on the outside, each being about 1 and 1/2 inches to the inside of the outermost dash mounting studs and one in the center about an inch and a half to the right of the center stud.

        I cut 3 scraps of plywood the same width as the backer and 2 inches long.  These I centered over the mounting locations and epoxied to the backer.  These two pics will give you a better idea of where we are headed here.

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        Once the epoxy hardens, again mount the backer and mark where the bolt will come thru from the back.  Drill a 1/4 inch hole thru the 2 layers of wood and the two layers of metal in each location.

        Removing the backer I then mounted the weld nuts in the holes.  I bent the flanges on each side of the nuts so the would dig into the wood and epoxied them in place.  You could do the same thing with 1/4 inch nuts by just enlarging the hole so the nut will fit into the scraps we glued on but not thru the backer.  Put a bolt in the nuts or inserts so they don't get epoxy on the threads.
        Once this is dry, you can bolt the backer in place by using 1/4-20 bolts from the back side thru the top of the dash which is how it is shown in the pics.  You want to add another strip of poly plastic under the backer because we do not want it glued to the metal in the subsequent steps.
        The two pics above and this one P1220003.jpg (81569 bytes) show adding the "brow" to the backer.  Again use a long 6-8 inch wide strip of cardboard and hold it on the top of the dash covering the defroster outlets and trace the curve of the backer from one side to the other.  The brow is going to mount on top of the backer and it will also extend towards the defroster ducts by about 1/8 inch so it is actually on top of the front cowl covering the seam between the dash and the cowl.  Not too much or it will end up interfering with the defroster escutcheon plates.
        Use a compass to trace the curve you got by marking the cardboard about 1 and 1/2 inches inside the curve.  In other words you want to have two concentric or parallel lines about this width apart.  Once you cut this pattern out it will be traced onto the plywood to form the top or brow of the pad.  Save the pattern for a later use.
        Trace the brow pattern onto the plywood and cut and trim as before.  What you want is a nice gentle curve with no dips in it since once it is upholstered only some really bad gouges would show.  I next used some small brads nailed down thru the brow while epoxying the brow to the backer.  It was also clamped as shown in the pic.
        Now we want to add some foam to the wooden backer.  What I used was an insulating foam used to sheath houses.  This is an isocyanate foam.  DO NOT USE STYROFOAM! IT MELTS WHEN FIBER GLASSED.  The isocyanate type should be available at most home supply or lumber yards or get "real" glassing foam at .
        Use the pattern you saved from cutting the brow and cut a couple of  curved pieces like it from the foam.  It is about 1/2 inch thick and it will take a couple of layers to make it thick vertically as the backer is wide.  In this pic you see the foam layers glued to the backer and held with duct tape.  I used liquid nails for this.

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        Once this is dry you want to fiberglass the whole top surface of the pad, both the wood and foam, with a layer of cloth and resin.  Again Fiber Glast is a good source for non directional mat which will follow any curve but the stuff you can buy at any auto parts will work.  Make sure to go beyond the forward surface of the brow a bit to cover the front edge.  This will all be sanded to shape when dry.
        Remove the pad from the car when the glass is dry.  Sand the front and back curves and the top.  Sanding and cutting the foam is done now as well and here you will have to use your own preference as to what shape you want for the final look.  I made mine relatively small and sloped the underside pretty drastically.  The pads on the real metal dash cars are more rectangular in shape.
        This is what mine looked like after shaping and sanding

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        Now if you did a real nice shaping and sanding job you could probably use the pad as is and upholster it.  I was concerned that after it was upholstered anything banging it would dent the foam underneath.  What I did then was to fiberglass one layer over the bottom side of the foam as seen here

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        This last shot shows the finished pad bolted on the car.  You can see the small cross section I chose.  I can make it heavier with padding and I plan on having mine black with red piping along the front to match the rear trim cover which came with my Moss panel set.
        Hope you liked the idea!

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NOTE: Tom Rynne is famous for the  "Windblocker", available everywhere.  He also produces some specialty parts for Chrome Bumper conversions, and has recently bought the molds from British American Motors, including the mold for the MGC hood.  His email is