You really do not want to be trying to feed that much demand to the battery through a 10 awg wire, especially if you ad fans and EFI. You need to figure the base amp draw of a stock system, then factor anything you have added, and add the draw for things you plan on adding. You will want to have 10-20 amps less total demand than the alternator when you are done. Unlikely you will encounter everything that draws amps operating continually at the same time, but you do not want the alternator to be under supplying the amperage required to keep the battery charging with a full load on the system. For example, you will likely never be putting the top up/down with the wipers running, flashers on, AC on high, high beams, laying on the horn moving the power seat and windows while waiting for the cigarette lighter to pop out. Unless you're Waterboy... You can run a heavier cable from the alternator to the starter solenoid lug and that the battery is connected to, and leave the 10 awg as it is. The bigger cable will not be that obvious. I will go out and take pics of how mine looks to give you an idea.
I upgraded to a 150 amp alternator in my 63 Riviera for the same upgrades. In a weekend you can do the same. Take lots of photos of the harness installed. Remove the harness and start at the farthest end and start unwrapping the non adhesive tape. As you come to a branch, put a wire tie there and continue till the harness is bare. Lay the upsized charging wire along the harness and start rewrapping the harness backwards. As you go remove the undersized wire and replace it with the new one. As you come to a branch, wrap that under the main wrap. You should be able to get the new wire to blend in and fit the original mount points. Id do the same to the starter and upsize the battery cables also. Not hard to do and will look stock. I’d up size it on more gauge to be sure you don’t have an issue with voltage drop. EFI’s are sensitive to that. Grounding is very important. https://www.summitracing.com/parts/aww-r0067108 Get a couple rolls. Ray
Sorry for my non-reply on this. I went direct to battery rather than down to the starter solenoid. Allegedly, though, (and I don't understand why) this bypasses the "voltage sensing" part of the three wire system. It hasn't made any negative difference in my system.
Thanks Brad - What route did you take to run the new wire to the battery? I assume you avoided the exhaust and took the shortest route, down by the timing cover past the oil filter?
