Here's a reasonable explanation:
http://www.autoshop101.com/forms/hweb1.pdf
Read the fusible link section and UNDERSTAND that it's purpose is to protect the wiring NOT the devices (that's the job of the individual fuses).
You can see in the article mention that some manufacturers are using maxifuses or fuse elements to replace fusible links. Obviously the KEY is to understand what rating the manufacturer's fusible links are before making a decision how to replace them.
Obviously the fusible link replacement MUST be very close to the battery, since the whole purpose is to have the fusing occur prior to any other wiring AND WITH WIRING THAT IS FIREPROOF (i.e. similar material as the existing fusible link is made of).
The fusible link is the last line of defense prior to your harness melting/BURNING, replacing it with some other mechanism requires you to really understand what your are doing...
I'm personally not sure what the fascination is with replacing them with something else on our 80's. The original links work just fine and are cheap. They should NEVER fail except for a catastrophic wiring short and then they will fail versus your vehicle potentially going up in flames. Keep a few spares. If you want to move stuff around in your battery tray, there is enough slack (if you uncover some of the harness - and then recover) to make some extra 'length'. Otherwise, spend the extra few dollars and get a battery with the correct post orientation.
IF you really want to replace them with a fuse or something else, read, read and read before just sticking a fuse/link somewhere in the engine bay as the replacement. Consider an accident where the harness gets pinched against the body etc and things short out.
cheers,
george.
