[HO455]

On a 37 amp standard alternator there is only the one fuseable link.

Normally fuses are sized 25% over the maximum expected current of the circuit. The problem on changing circuits is that if you have a 50 amp alternator wired with 8 guage wire then the fuse should be 62.5 amps by the math. So you would choose a 60 amp fuse.
The fuse will provide short circuit protection but not over current protection.

If your battery is demanding 54 amps the 8 guage wire from the alternator will be carrying more amperage than it is rated for. (Most alternators will supply more amps than they are rated for.) Eventually if this condition continues the installation on the wire will fail, causing a short circuit. By the time the melted insulation causes the fuse to blow the damage is already is done to the wiring.
If you replace the 60 amp fuse with a 50 amp fuse every time the alternator goes to full charge rate the fuse will blow. An annoying condition at the least.

At this point you have 2 choices replace the 8 guage wires with 6 guage or replace the fuse with a fuseable link.

Up the sized wiring would give you a very robust harness but at a greater cost.

The correctly sized fuseable link will give the circuit the overcurrent protection it needs and give adequate short circuit protection. By adequate I mean if the harness gets shorted to te frame it will take several seconds for the fuseable link to melt cutting off the connection to the battery. There might be additional damage caused by that delay but it should prevent the truck from catching fire.

For some reason on our trucks GM installed an insulated post in the circuit to make replacement of the fuseable link easier. Something they didn't do on cars of the same era. We could speculate for hours on why they made the decision to spend the extra money. If you want to delete the insulated post on your truck there won't be a problem.

I'm just trying to provide some information on things to consider when you make changes to your factory wiring. We've all seen pictures of restored or modified vehicles on fire. You never hear the reasons why but I would bet most start as a result of improper wiring.

Please do not use the example I listed to make choices for your system. It is a simple example to help explain the considerations involved.