[LS short box]

On my 68 C10 project I used a Painless wiring kit with a 60 amp Maxi fuse. Zero issues. But I wasn't running a big stereo or anything like that. That 60 amp fuse should only be running up to the fuse block on the fire wall. Please check with Painless.
On my swaps (LS) I ran a 6 gauge wire from the main stud on the starter to the stud on the back of the alternator. No fuse on that wire.
You can just see the Maxi fuse under the heater box.