Please don't add a "let's see if this doesn't blow" fuse to your glow plug system.
You can get the fusible link wire from a number of sources but this seems to be the most commonly available packaging.
https://www.oreillyauto.com/detail/...-fusible-link-universal/flc14bp/4414532?pos=3
The wire in the package is labeled 2.0 sqmm
For the GP system Ford used two 4-5" runs of the 2.0 sqmm fusible link wire that was soldered onto maybe a 4awg wire headed to the GP relay.
Your GP system shouldn't pull more than 80amps for a short duration I think? Maybe even less I can't remember off the top of my head. Fusible link protection is almost purely for short circuit protection, not "overload" protection (yes a SC is an overload but it's protected against differently). Inrush current is pretty high but that drops pretty quick for what we are discussing here. A 200 amp fuse in this kind of system is going to suport 200 amps of current for a long duration. So if you put that much fuse inline it's best to make sure you have cabling that can also continuously support that much current. If you don't, and say your relay welds it self closed, then you've got full current being drawn continuously (again maybe 80amps). That's going to get that wire pretty hot but probably not cause a wire in good condition it to melt and SC. Now we add 20 years of heat and vibration to our wire and now the relay welds it self. Now we've got a hot wire with weak insulation and chaffing that say leads to a melt through and a small current leak. With the already loaded system it won't take much of any kind of additional current bleed to ground to overload the fusible links and they melt away and the circuit is opened and safe. Maybe even the damaged section of the wire can be repaired. If you have replaced the fusible links with a 200 amp fuse, that fuse is going to allow up to 200 amps to pass through a wire that is not capable of supporting that load increase in an already loaded system. You will have significantly more damage to that wire as well as every wire that it touches as it runs through the harness. I would not recommend using a fuse for the glow plug system vs the fusible links unless you know how to select the correct style of fuse for this application. It's not just picking one capable of handling the max inrush.
I disagree with the above. Fusible link or a fuse, they both serve the same purpose. I am sure your fusible links would pass more than 200 amps for a period of time before they burnt in two. Just like a 200 amp fuse has a short time period before it blows.
I like fusible links. They are small and compact, and can be wrapped in the harness out of the weather. But their function is the same as a fuse.