I built it yesterday. It seems to work fine! I haven't gotten around to putting it in the truck yet so I don't know how it will work with the full load of the Disty and heater on it. I tested it with a couple of bulbs and it doesn't even begin to get warm. I will keep you updated when I put a real load on it.
For heat sinks, I used two pieces of 1-1/2 x 2-1/2 x 2-1/2" long aluminum angle. one for the regulator, and one for the transistor. connected by a piece of sheet PVC. The angle that the transistor is mounted to is +12V. The one that the reg. is mounted to is +1.2 to 13.8 low power. A third angle to mount it with is Gnd. The emitter is connected to a terminal strip which is +1.2 to 13.8V high power.
I have less than $10.00 invested in this thing, and it is an interesting enough project that, even if it doesn't make the final cut, is well worth what I spent.
