A number 2 is too big for coming off the back of the alternator, a number 6 is sufficient. That alternator stud is metric, but a 1/4 inch ring terminal will fit just fine. That plastic piece is what the rubber isolating boot slips over that protects the connection from an accidental short circuit. Ford installed that on the alternators.

Use the number 6 from the alternator through the Mega fuse and back to the solenoid or battery terminal or set an auxiliary power block as BB suggested. Use the number 2 to go from the battery to the solenoid and solenoid to the starter. The bigger cable will help carry power to the starter when it all gets heat soaked.

Last edited by Bolted to Floor (7/22/2019 9:32 PM)

1fststang wrote:

Right now I have the bat+ terminal going to the solenoid as well as another + cable that goes to the mega fuse.  That is about all you can attach to the stud.   I have power for my MSD box and my electric fan controler plus what ever wires go from my AWW wiring harness.    I can attach my msd and fan wires to the lug on the mega fuse.  

 Sounds like you are at a point where you need an auxiliary fuse block or several MEGA or MIDI fuse holders daisy chained together since the MSD box, fan controller, and AAW harness all need fuse protection too. Ford used a fusible link to project the wiring coming from the alternator. Painless gave me a 70A fuse to protect the main feed to the fuse box. What did AAW provide for their harness?

1fststang wrote:

As far as the cable size most recommend a 4 gauge and I figured for a few bucks more I could use 2 gauge and not have to worry about it.  If a heavy gauge wire is necessary to carry the 130 amp alternator I don't see how you can use a small cable like 6g from alternator to the one side of the mega fuse and what would the point be to use heavier on the other end of mega fuse to battery ?

Maybe I can just change the lug on the end of the 2 gauge to fit.  I see them online for 2g wire with 1/4" stud I just need to look at the dimensions to see if it will fit within the insulator on the alternator.
 

 Its not just the size of the wire that counts, the type of insulation plays a major role in determining ampacity. I used #6 SGX cable and a 130A fuse. I didn’t see a reason to go over the alternators capabilities. That MEGA fuse is protecting the car from the alternator. So, you can run the same size wire from the alternator through the fuse to the solenoid. The battery + to solenoid and solenoid to starter benefit from the number 2 because there will be less voltage drop during starting as compared to a smaller size wire.  Yes, you should be able to buy lugs with different stud sizes, do make sure to check the dimensions.

#6 wire is perfect. You aren’t planning on doing any welding with that alternator, are you?
Be sure to use a heavy duty terminal made for the #6 wire. Buying them from a REAL electrical source or even the marine section at Ace Hardware will get thicker ones than the crap they sell at Autozone or OReilly.