I picked up a similar charge cable from the JY like the one pictured to use in a 3G alternator conversion on my 91 F150.

Only problem is, I'm missing the MEGA fuse holder and cover.

Couldn't I just pick up an aftermarket Mega fuse holder?

If anyone has one of these OEM holders w/cover, I'll be glad to take it off your hands.




Charge cable picture is bottom highlighted in red. (Notice small 20amp fuse holder clipped on side of housing.)

 

What is in your picture is the 97-02 F150/Expedition Mega Fuse block setup. It took awhile for the picture to load, so I am making it clear with basic text for clarity.

I just got done replacing the block on my 97 Expedition due to the original breaking apart. Original ones have Zinc-plated hardware and thin bases (probably ABS plastic). The hardware rusts together, the owner tries loosening it (such as when replacing the fuse) and the studs break loose from the base in the process. This is how mine failed when I attempted to remove the cables for cleanup.

After looking at all of the commercially available options, all I found were the same two design/material failures. Seriously?? who makes a fuse block with mild steel hardware that will rust together and break the base??? Come on Littelfuse, you know better than that!

I ended up building my own from scratch using entirely stainless steel hardware that locks into square holes and is surrounded by the solid base material with no "web" reinforcements needed. The result is a strong, electrically sound part which won't vibrate loose or corrode. The base and backing plate material was leftover high density polyethylene from another similar electrical project on my RX7.

My first attempt used M6x1.0 bolts and didn't go very well due to leaving the back open which shorted out and melted the plastic. Plus, it's kind of difficult to machine a precision hex by hand. M6 bolts heads are 10mm flat to flat and 11mm point to point, so you have to be REALLY accurate or they'll just spin in the holes as mine eventually did.

The second block that I finished up this morning uses 3/8" carriage bolts (9.3mm actual measurement). After grinding the threads off by hand and getting within 0.004" of my target diameter (8.0mm), I had them re-threaded locally to M8x1.25 to mimic the original block. I'm not the world's best machinist and my setup was definitely not elegant (bolt in a drill, applied to Dremel clamped to the bench), but it worked well enough. Also, I mostly just eyeballed it, verifying it with a digital caliper from Harbor Freight. The shop was more impressed that I got it so close, saying that it was about as accurate as they could do. Even with re-threading them, it still cost less to do it this way than buy M8x1.25 carriage bolts at $7.25 each from Fastenal.

If you apply the Pythagorean Theorem, the corner to corner measurement is roughly 13.2mm, giving it far more surface area to resist spinning in the hole. Roughly 41% more area IIRC, compared to M6x1.0 hex hardware.

Here's the math for you:
5/16" or M8x1.25:
Shoulder square: 7.8mm
Corner to corner: 11.03mm
Diagonal-Side ratio: 141.4%

3/8" or M10x1.25:
Shoulder square: 9.3mm
Corner to Corner: 13.15mm
Diagonal-Side ratio: 141.4%

The ratio of side to diagonal measurements are the same, but the larger hardware has more area to spread the torque over, making it less able to spin. Also, any heat it sees is spread over a greater contact area as well. Result is less heat buildup so it can't distort the plastic base as easily.

To prevent shorting, I made a backing plate to cover the carriage bolt heads and just bolted it on, then attached the whole assembly to the stock bracket after lopping off the stock fuse holder ears. With some stainless locknuts so the electrical connections can't vibrate loose, it should be reliable for years to come.

In total, I spent about $15 to build the block. The biggest cost was that the shop charged me $3 per bolt to re-thread them. In retrospect, using 5/16" carriage bolts and locknuts would have been far cheaper as the nuts are readily available in a bulk pack instead of $0.70 a piece and there would be no re-threading necessary.

 

My 99 tahoe has a mega fuse holder on the radiator shroud. I don't remember how it's made exactly, but I didn't have any problems with it falling apart when I changed the fuse. I did have a problem with the rivets holding the fuse together getting loose and giving me a bad connection, but no problem with the holder. The pickups may have them also. I do know a friend had a 96 tahoe and it did not have one though.

 

Interesting, can you get a picture of it? Never hurts to see what's available too

 

It looks just like this one on Amazon.

 

I considered those, untill I saw what they pulled where you don't normally see.
Mega® Style Fuse Bolt Down Fuse Holders and Fuse | eBay

3rd picture shows the same manner of failure as the stock setup. ANY stickiness on the bolts and they'll rip right through the 1mm of plastic surrounding the bolt hexes. Not acceptable by ANY means.

 

Here are a couple of aftermarket fuse holders I've looked at and some pros and cons:

This one seems popular...Cooper Bussman FMG-211. It's made of black thermoplastic with zinc-plated steel studs; thermoplastic elastomer cover. Doesn't seem like the best for high heat conditions.(?) But, does completely cover the fuse fasteners and allow full access for cables.
http://www.ebay.com/itm/Cooper-Bussman-New-FMG-211-Fuse-Block-Holder-Mount-AMG-High-AMP-MEGA-Fuses-Buss/272084978587?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35934%26meid%3D261dc1d3944648499abd6737b3f31b1c%26pid%3D100005%26rk%3D2%26rkt%3D4%26sd%3D121938207924
I might buy one of these... It's from MTA. Cool thing is it's made of Ultramid® A3WG6. Same material that automotive radiator tanks are made of (not likely to strip out under torque. Plus, both ends of fastener is accessible when opened).
http://www.ebay.com/itm/381386757857?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Littlefuse makes several different types. This one is interesting...it's called the Flex Mega Fuse Holder. It seems to be better constructed than the basic 298. I wonder if anyone has used this type and can provide any feedback?
Mega Fuse Holder High Amp Fuse 12V Battery Power Distribution Block Mega Flex | eBay


Travis, you got pictures of your home made setup?

 

These aren't the best pics, but it helps illustrate the idea about using the base material correctly to stop the studs from turning


In progress, a typical ADD-fueled workbench project




~90% done, but functional. All I did beyond this was lop off the bottom to clear the big connector that clips on the bottom of the bracket.Every piece of hardware has breathing room surrounding it so it can dissipate heat into the air. I'm hoping this will make a difference compared to my last attempt. The stainless steel bus bar on the left side studs is there to eliminate one of the cables from the starter relay. Two fewer connections means less possibility of corrosion.