I'd use a mega fuse or a fusable link like the factory. It should never blow unless you have short in the alternator or power surge.
The Explorer uses a fuse on the power distribution box which I'm using on my conversion. I used a stock alternator wire on the last one which makes a nice clean install. It's the wire with the 2 white fusable links at the terminal. That one is off a 94 Mustang 5.0.
Some will recomend not running a fuse or breaker at all. The 3G can dump a whole bunch of amps and volts in the case of a failure of the internal regulator and other reasons. One reason to keep the alternator connection as close to the positive terminal of the battery as possible. Many vehicles run that wire directly to the post. The battery will absorb big power surges. The farther your alternator connection is from the battery and closer to the rest of the electrical system, the greater your chance of frying things due to a voltage surge. More important if you are running EFI or other valuable electronics such as your GPS, stereo, etc. All of the auto manufactures provide this protection. A loose (intermittent) connection at or near the alternator can cause a phenomena called "load dumping" which can cause a large power spike. (voltage and currrent) Use a link that is about 140% of the alternator ratinig. 175 amps for a 130 amp alternator.
