On the wiring diagram for your alternator, it does not show the white wire looped. It shows no connection to the white wire on the new plug you just bought. I would cap it off with some tape.

It did not have a fusible link originally in the black output line by itself. You did originally have a fusible link at the starter solenoid connection though. In other words, you have another wire or wires at the battery + solenoid connection correct? These run the whole truck. And I assume they have been modified like all the other wiring? Originally you had one large wire coming off the starter solenoid battery + connection, and this ran to one fusible link. After this fusible link, you have a splice with the alternator and the rest of the truck wiring connected together.

 

Might have been me, but for a different application.
If I'm not mistaken, the whole "white wire connects to the side of the alternator" bit is for a 3G only. Not a 2G like yours.

According to the diagram the white wire is for one, or two things only.
1. To help heat the choke coil to open the choke plate up. Or whatever it does on an EFI engine? I don't know, but it's there in that previous diagram.
If you still have a stock electric choke (on a stock carburetor?), you can re-connect it there to the old wire.
2. Runs to a connector on the ECM on a 4.9l engine only. So if you are using the new computer for the new donor engine, you don't need the wire connected to that either.

In other words, just do what Franklin said unless you find another matching White w/black wire that needs it's power source back.
Looks like the old one was taped off too though?

Hopefully I'm remembering your thread correctly and this was a swap from a 4.9l inline-six to a V8 engine. Correct?
If not, sorry for mixing things up. If that's correct though, then with the new V8 computer you do not need the wire.

Sounds like you're comfortable adding fusible links, but if it was me I'd use a replaceable fuse (or even a circuit-breaker) instead. Just easier to deal with...
A Midi-Fuse, or a Maxi-Fuse rated at about 100 or 120 amps or so. I forget what your alternator is rated at, but if 75a or so, then a 100a fuse is fine. If it's a 95a or similar rating, then a 120a fuse would be the better choice.
The two fuse types mentioned are available with their own specific holders for a nice clean installation. Keeping a spare fuse or two with you in the glovebox will get you back on the road quickly if you have any issues in the future. A circuit-breaker is the ultimate protection probably, but at a much greater cost up front.

Adding protection to the charge circuit is not a requirement for the alternator to function. It's simply a good idea/requirement for protecting the wires and other stuff from a problem.
Taking the two Black wires then from the main output connector of the alternator and connecting them through a fuse first, before connecting to the battery side of the starter relay/solenoid is a good thing.

Paul

 

"The White Wire"
Short answer is to connect both white wires from both new plugs together and also run this to the electric choke.

Background info.
In 1986, as the diagram in post 24 shows, 2 wires to the Voltage Regulator (VR) plug worked fine. In 1987 they used 3 wire on the same G2 ALT VR plug. If your ALT is very old, 2 wires will still work. Newer G2 and G3 Alternators (including rebuilds) need all 3 wires. My gut feeling is the are just using G3 VR's on G2 ALT, the plug is the same.. When the auto parts store bench checks the ALT they use all 3 wires on the VR plug.

I would add some protection for the charging wiring. Either a fuse link, mega fuse or CB. Back to the diagram in post 24, fuse link J provides protection for the wiring charging the battery via the ALT.

Originally, the white wire also went to a "auto diagnostic check" connector on the inner fender, near the battery. Most likely long gone on your truck.

Thanks for the follow up post.
Jim