to power a generic fuse block, would I run power from the Batt. terminal on the ignition switch, running the Acc. terminal in parallel? Or should I run the fuse block off the fourth terminal on the voltage regulator? I think running off the fourth terminal would only give me power to the accessories while the engine is running.

Need more info to answer your question. Is this a replacement fuse block or a add on one? What kind of power are you needing, bat , ign, acc or ??? Don't wire anything off the voltage regulator.

A lot of this depends on what you are doing...

For example let's say you are adding electric fans or some other accessory device up front. Here you might want to put the add-on fuse panel on the cowl support with power provided off of the horn relay bus bar. Now perhaps you do not want the accessories to be powered all the time... so you would add a relay to the power feed with control from the dash harness ignition or accessory hot as desired.

As another example say you want to add some serious kick butt stereo and amps so the music will be louder than the engine. This points to a fuse panel inside the firewall but brings up the question of where to get power from. If the devices are moderately powered you can use the extra taps on the factory fuse panel. But if the amps require welding cable power feeds... well then you better run a seperate power feed wire from the horn relay bus bar and use a relay to switch it on/off from the factory fuse panel taps.

i have wired the ignition switch, coil, alt. n voltage regulator, and starter. that's it. all other wires are completely gone from the car. I can run all the wires, switches and lights needed for my head and taillights, brakes, reverse lamps, etc.
I just need to know where the power supply comes from for the fuse box. Is it straight off the battery, or off the ACC. terminal?

I don't want to spend 250 to 300 on a wiring harness when I have rolls upon rolls of every guage wire readily available. the car just has to pass inspection to get a tag so I can drive it to the track. should have VERY limited street time.

What vehicle?

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