They should be time-delay fuses to simulate how a fusible link functions.

I think you missed my point. The fuse was only there as an expendable part of the tests to find the culprit. Not to permanently replace the fusible link. But I have used normal fuses with no ill effects to replace the fusible link before. Of course, I have always had my headlight circuit on relays to significantly lessen the load on the rest of the harnesses and bulkhead connectors. I have seen my share of melted column wires and bulkhead connectors because of the load the headlights put on them.

Probably Fusible link but could be the power connector at the bulkhead or steering column.

Get a voltmeter or test light. It helps to have long black wire to be a dedicated ground the test light/Meter direct to the battery It eliminates the hunt for a good ground while lying on your back under the dash.

1. Check for voltage at the battery terminals on the post and the clamps on terminal. Also check for voltage at the positive terminal and grounded at the engine to be sure the negative cable isn't shot.
2. Follow smaller of the two wires coming from the Positive battery terminal. (Large one goes to the starter) until it meets a connector or connects to the starter relay.
That connector or the wire coming from the starter relay that the battery wire connects to should be the fusible link. Check for voltage at both ends of the fusible link.
If voltage is only on the battery side the link is burned. DON'T REPLACE IT YET.***
3. If you have good voltage on both sides of the fusible link, follow the wire that is the fusible link to the bulkhead connector. Check the voltage at the bulkhead connector and check to be sure the wire going into the connector isn't loose or burned.
4. If the connector seems good crawl under the dash and check for voltage at the back side of the bulkhead connector. If good voltage at the backside check that the wire is tight.
5. Check the large wire going into the ignition switch for voltage. Check both sides of the connector.
6. Turn the switch to the run position and check for voltage coming out of the switch.

At this point you should have narrowed it down. Repair the bulkhead or replace the ignition switch as needed.

***If the fusible link is blown you need to find out why before you replace it. I have a 30 amp 12V circuit breaker I replace the fusible link with during the search for the short.
a. Check for a grounded main wire on the alternator. Inspect the wiring to the Alternator. Fingers crossed this one is easy to fix. Replace the alternator.
b. Check for loose, burnt or bad connectors on the back of the ammeter. It is easy to unbolt the wires from the ammeter and bolt them together covered in electrical tape to see if that resolves the problem too. Fixing the ammeter is usually just removing the dash cluster and replacing the insulators on the ammeter. Ammeters are often the problem.
c. The other thing to check is to see if the ignition switch is grounded. I have had them come apart and ground inside the column. Remove the connectors and check for a ground on any large wire.
d. Lastly start looking for burnt wires from the alternator to the bulkhead connector and then under the dash. It may be a rewire time.

Hope it helps.