Its not hard as it seems. i got the air dam off a 83-88 ford ranger from the local junkyard for $10, a new one is $80 or so. Did a little trimming arpound the edges and I drilled the same four holes from the old air dam on to the new one. It gives the car a tougher look. I really like the outcome.
CUSTOM FRONT AIR DAM
This air dam was an OEM part for a 1983-1988 Ford Ranger that has been modified to fit a Fox3 Mustang to improve cooling by creating more air flow to the radiator, increase gas mileage by improving the areodynamics, and also improve the overall appearance of the car when viewed from the front. This air dam was also seen on the older orange Fox3 Mustang GTs of the Bob Bondurant School of High Performance Driving... so, I'm not the only nut using it on a Mustang!
Click on image to view a larger version OEM Air Dam
This is the air dam fresh out of the plastic package from the Ford Dealership (Ford Part Number: E3TZ-10001A06-B). Some modifications were necessary to fit it under a Fox3 Mustang and still have a factory appearance.
Support Material Trimmed
The top of the support material that rests against the bottom of the Ranger's front bumper was removed using a belt sander to allow the air dam to fit flat against the underside of the car.
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Click on image to view a larger version Corners Trimmed
The top corners of the air dam were square to match the Ranger's front bumper and were trimmed at a rounded angle to match the shape of the Mustang LX's curved front fascia.
Note: The corners do not need to be trimmed for fitment on a GT Mustang as the front fascia is wider and straight, however the top of the corners still need to be sanded flat with a belt sander to allow the air dam to fit flat against the underside of the car.
New Mounting Holes
Four new holes were drilled to match the Mustang's original air dam mounting holes (original air dam used as a template). The new air dam can now be bolted to the car with the original bolts.
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Click on image to view a larger version Outer Edge Mounting Brackets
To support the outer edges of the new air dam, an L-shaped bracket was made from sheet metal and attached to the underside of each metal fender (behind the fiberglass fender extensions) using a screw and speed-clip. Once the outer edge brackets were in place, matching holes in each end of the air dam were drilled to attach it to the brackets from the outside using another screw and speed-clip.
I made one for my car, I made it out of thin aluminum metal sheet that I had. It works real well and is very sterdy. It has held up pretty good. look just under the front you will see it sticking down.