First of all thanks for all of the kind words! :>)
Answers:
Styrene is a type of plastic. I have it in sheets from when I did Model Railroading heavily. It is the material that 1:25 cars are molded in and it is also the material that your current cluster housing is made of. You can buy it at any model shop. I laminated several sheets to get it to the same thickness as the panel.
After stripping all of the gauges and the metal from the panel I used a chisel point Exacto blade to trim off the raised edges on the front. I then traced each hole and cut a "plug" to fit and glued it in. Once it was filled flush I added a single piece at the rear to bind it all together and give it more strength. I then made a pattern and cut a piece of .090 aluminum to fit into the face. I drew the panel face in Autocad and layed out the gauges and printed it out. Used the center of the gauge holes as a start and drilled pilot holes. I then clamped it to the cluster bezel and drilled the same pilot holes in it. For the 2-1/16" holes I used a 2" chassis punch (Aircraft gauges) and opened the up (slowly with a sanding burr in a die grinder). For the 3-3/8" holes I used a 3 1/4" holes saw and did the same thing. I clamped the aluminum very well when using the hole saw and I just knew that the last hole would get screwed up! But it didn't. Painted it black with Dupont flattened to semi/matte.
For wiring I used terminal strips mounted to the rear of the bezel/cluster and wired all that I could to the plug that I cut out of the circuit board that used to run the stock dash. I cut it in a circle and drilled holes in the copper foil to solder my wiring to. And the whole assembly can be removed with 4 screws and that plug. I used some of the unused pins for things that the original dash did not have.
My light and wiper switches are mounted on the main metal dash right below their original location. I aded a push button just to the right of the wiper switch for the washer pump.
I looked and I don't have any pics of the rear (it is pretty ugly)
I still have a three hole panel below the ashtray. At this point I only have 2 guages (both Westech A/C gauges). One for Manifold temp and a dual EGT. I had a bung welded into each pipe for EGT probes and an O2 sensor bung in each of the collectors. I then hade them ceramic coated.
Gotta go dinner is ready. BLTs with my home smoked pepper bacon! :>)
Scamp
