Question about a old mad bypass repair

The thing is, the OEM was AFU, both for wire gauge and for fusing, / fuse links. PERIOD, (except maybe for the earliest ones with a 35--37A alternator!!!!

I hope you are using much larger wire than original, and you need to at least size that by the largest alternator you ever expect to use, as well as fuse sizes.

The essence of the MAD swap, however you do your version, is this:

When you get through all the loops and twists in the harness, AND the bulkhead terminals are properly fixed, or bypassed, the old ammeter wires end up in PARALLEL to form one large wire which is now supplying power to the interior, AND there should be no charge current through the bulkhead anymore, which then, RELIEVES those wires of that part of the load which they formerly carried.

The main charge line should now be a nice big fused/ fuse link protected jumper, direct from the alternator output to the battery positive post.

If you have a 45-50 ish alternator, I'd use about 60A fuse on the charge wire
If you have a 65 ish I'd use 70-80

If you have an alternator larger, I'd make DARN sure the wire sizes are up to snuff, and on the charge wire, use 100Aw

If you have the through-the bulkhead circuit properly built with however you modded it, there should be no charge current. That fuse depends on accessories. EFI/ fans/ pumps, huge stereo, whatever. A bone stock car loads wise, you should be able to get by with 40

MAKE SURE the fuse is AWAY from engine heat which degrades amperage

Make SURE the fuse holder is QUALITY, as loose connections heat up the fuse and degrade rating.

Probably the best fuses are the so called "maxi" type or other fuses with screw/ stud connections.