Lots of years ago, late 80's maybe, I replaced the fuel pump fuse with an inline fuse/holder. I have experienced NO other fuse block problems. 1978 Targa, fuse didn't fail, only the holder, and at the WORSE possible time.

I was first in line to get off the ferry as it docked...ended up trailing a line of traffic rather than leading it.

Ordered a new fuse block section, which I believe is still in the back of the glove box.

Here are some quick pics from my current fuse box. Might be useful to other folks.
Linked because the PP board drops the resolution too much to be useful.

The labels here are what is printed on the cover. The fuse amperage is what I found in that slot. The amperage is not necessarily correct.
Fuse Box Cover Label
Fuse Box Image - High Resoultion
http://forums.pelicanparts.com/uploa...1400091392.jpg

Only fuses 3 and 4 appear to be ganged from the front. Further analysis with my multimeter and checking the back will determine which others are ganged.

A previous owner has messed with these - do not assume a normal SC should match this.

From the back you will see this:
http://forums.pelicanparts.com/uploa...1400097525.jpg

Since you will use this type of fuse blocks
http://forums.pelicanparts.com/uploa...1400097758.jpg

I suggest that you check Algernon's post, he used the same fuseblocks.
http://forums.pelicanparts.com/porsche-911-technical-forum/772278-cheap-easy-ato-fuse-block-installation.html

Connected fuse positions
 

I believe that you will find that the following fuses are jumpered together on the top side of your old fuse panel. You can verify the info with a VOM:

16-17 Low Beams
14-15 High Beams
10-11 air blower- rear window and stop/turn signals
7-8-9 Cig lighter, rear wiper and windshield wipers
4-5 Interior lights and heated windshield warning light

This should be true for all SC cars (78-83). Hope this helps with your project.

Hmm, I read Algernon's thread, but didn't see the immediate correlation to my stock SC fuse block. He has these funny "extra" top edge screw contacts which I don't, so I'm not sure mine is ganged in the same way as his.

Hopefully I'll have time to attack it tonight and see exactly what is going on on the back of it. The more I see, the more suspicious I am that serious re-wiring has happened in the past.

you are in for a lot of clean-up work, but I'm confident the outcome will be worth it. Note, you have no connections to any of the headlight fuses, high or low beam, no screws, no power in, or out.

The good news is it should be pretty straightforward to clean it up and make it work, it will be a little more involved to make everything work the right way. I am sure you will find, when you flip the stock fuse blocks over, you have the standard gang-arrangement, the wired-jumpers were put there by previous hacks

I'm assuming there are some headlight relays and fuses outboard of what your picture shows, and I also am scared by those two blade-fuses taped together, and the blue butt connectors under fuse 12 or so.

Can't wait to see the before & after photos.

I took a first whack at the job last night. I removed the last original block, which has 8 of the fuses on it.
Of those, only numbers 18, 19, and 20 were actually used. 21 had wires to the bottom of it, but nothing on the top. I removed that block and replaced it with my 6 fuse block. I hooked up the wires into the same positions on the original block, including the unused number 21.

The original fuses were 5 and 16 amp. However I couldn't find ATO in 16 amp, so I'm using a 15. While this isn't quite correct, I don't foresee any issues with running slightly lower amperage fuses. Thoughts?

For now, the new fuse block is held in with wire ties. I plan to acquire a plastic ruler as a new mounting bar. I'll drill the rivets out of the new blocks, and epoxy them on to the ruler. Than I can drill holes in the ruler and mount it with the original screw holes.
This seems better than drilling new holes into the base plate, and putting tiny nuts on the backside.

I tested the three new active fuses (18, 19, 20) and they are correctly controlling the blinkers and license plate light. I suspect the taped wiring and fuses are relays for the headlights, installed in a poor way.

Before:
http://forums.pelicanparts.com/uploa...1400163476.jpg

In Progress:
http://forums.pelicanparts.com/uploa...1400163493.jpg

After:
http://forums.pelicanparts.com/uploa...1400163507.jpg

I put fuse 21's wires on the top instead of bottom. Doesn't matter because that fuse isn't used, but I should fix it.

And an updated table based on my better pictures:
http://forums.pelicanparts.com/uploa...1400165273.jpg

Mounting your fuse holders..........
 

Go to Lowes or Home Depot and buy a 2" wide aluminum strip. Drill mounting holes in the aluminum strip and use bevel headed screws (from the back) to mount the fuse holders. Then you can simply drill holes thru the aluminum and use 4mm cap screws to mount the assembly to the bracket. This should be much more secure than gluing it together!

Not sure what the 'extra top edge screw contacts' are you refer to? The extra red wires at the top are substitute for original hidden links.
Also, be aware the tops of the ATO fuses get very close to the fuse box lid - adding an al. strip or plastic ruler might stop the lid from snapping on. I used sheet metal screws to attach the holders directly to the fuse box frame where the original holes didn't line up.
If I can help, PM me, anytime.
http://forums.pelicanparts.com/uploa...1400206526.jpg

Well last night I picked up a piece of aluminum at Home Depot for $8. I drilled out the rivets on the 15-fuse block. Then I marked out where I'll be attaching the little 3-mount fuse blocks.

I picked up some screws for attaching them to the aluminum strip, but the screws were too small so I'm going to need to pick up some more.

With the new strip, I should be able to also fit my two headlight relays. Also, I won't have to make any extra holes in the fuse mounting panel in the car itself.

http://forums.pelicanparts.com/uploa...1400246643.jpg

http://forums.pelicanparts.com/uploa...1400246657.jpg

Much better........
 

Now you are on the right track! When doing jobs like this it is better to think "permanent" rather than "quick"! One thing you probably should check is the max amperage load per section. If you use 3 20 amp fuses in one 3 fuse section you might be overloading it. Better safe than sorry! Good luck!

That's the best solution I've seen so far! Congratulations. I wish I had thought of de-riveting the fuse blocks and re-assembling them on a new strip! Maybe you could counter-bore the strip and re-rivet the fuse blocks on?
BTW, the fuse blocks are rated high enough to not worry about overloading them with 3 x 20A.

I was pretty busy this weekend, but I did finish drilling out the mounting bracket, and got correct screws for attaching the fuse blocks.
Now I need to pull out the block I already installed, and then I can put the new one in.
Once it again works, I'll move on to mounting the relays properly.
http://forums.pelicanparts.com/uploa...1400505361.jpg
http://forums.pelicanparts.com/uploa...1400505373.jpg

The alignment isn't perfect, but its pretty close!

And here's what kept me busy Sunday - waxing that baby!
http://forums.pelicanparts.com/uploa...1400505406.jpg

She's done!

Before
http://forums.pelicanparts.com/uploa...1400091392.jpg
After!
http://forums.pelicanparts.com/uploa...1400678593.jpg

It was a real pain getting some of the bigger gauge wires into their spots, but I eventually got them. I used very large gauge wire to make the necessary gangs. I was able to reuse the gang that was originally from slot 3 to 4.
The screws I used for holding the fuse blocks onto the mounting strip were #10x1/2"
In the end, it took about 3 hours to connect the wires, gang the necessary ones, and then double-check every connection, fuse value, and gang.

But she works great, and it is much cleaner now! Next I need to take out that messy relay setup and mount those relays and fuses in a professional setup.

Could you expand on this ?

Adding relays does not remove the necesity to fuse the headlights. Of course you wouldnt fuse for the milliamps running throught the switch but you would still need to fuse the power on the secondary side of the realy that is feeding the lights. Unless of course you meant that your fuse for the lights is elsewhere now that you have the relay .

A well written DIY article would be most likely an addition to the PP brain trust. I have been thinking about the upgrade myself.

After reading the many responses, spending the money with Fred Cook would be the most efficient use of your time and effort. His prices seem reasonable to me.

Grant

Yes, I used 4 relays with built-in ATO fuses! The 4 feeds to drive the relays came from the switch via 2 original fuse lines, re-fused to lower value, saving 2 positions. The power to each relay came through 4 dedicated new lines direct from battery. So no lines, fuses or relays have to cope with more than 1 filament.
The 2 yellow and 2 white wires coming from fuses 5 and 6 go to relays, leaving 7 and 8 which I then used for oil cooler (red and yellow wires). Hope that's clear?

http://forums.pelicanparts.com/uploa...1400728729.jpg
http://forums.pelicanparts.com/uploa...1400728795.jpg
http://forums.pelicanparts.com/uploa...1400728916.jpg
(I ran out of red fuses for the relays, hence temp. blue one!)

I'm not knocking Fred, but I just could not bring myself to add quick-connects to every last wire going to the fuse block! My back would not stand it, and I was not sure if this would create another source of uncertainty if my crimping was not perfect. The original Porsche wire ends just pushed directly into my new fuse holders in most cases. A few big reds needed help. Less work and 10% of cost worked for me. YMMV.