It will probably work fine as you have it. But theoretically, the less connections the better for the large leads. If you are pulling around 100 amps, even a very very low resistance can cause some voltage drop.

The best senario would be to buy a new battery + cable that is long enough to go from the battery to the large terminal on the new starter(Eric's suggestion).

Then come off the battery + terminal with at least a 10, possibly and 8 gauge wire, and bolt it to the old Ford solenoid large terminal were the bat + used to go. This will take care of feeding all the electrical in the truck, since this is the factory junction point for that.

Then do as you suggested, and run a 12 gauge from the large post on the other side of the Ford solenoid to the solenoid on the new starter(I think you said this was "ignition").

By hooking it this way, the 12 guage will be less affected by any voltage drop problems in the large wiring, since it will have it's own connection through the Ford solenoid, to the battery +, and the Ford solenoid should last forever, since it now only has to carry the new starter's solenoid load. And the large wire will have less connection points(or splices) and two less switch contacts to cause problems and resistance.

 

That makes perfect sense. I like your suggestion. I think I will change it to the way you recommend. I am sure I have the materials on hand to build up some more custom wiring.

Thanks for the suggestion and also for clarifying Eric's post for me.