I've always seemed to have a voltage issue since day one of owning the car, it's never too low but in the summer when it gets hot and the a/c comes on it goes down to borderline "red" on the gauge. I have also tested it with a meter to make sure the gauge was reading correctly, and it is.

I'm planning to go over pretty much every ground wire in the engine bay, what are some the important ones that i should be looking at or replacing that can cause huge resistance issues? I know the ones behind the drivers side head are good, i cleaned them up pretty good while doing the heads and cam swap. I'm also looking to order a grounding cable kit, will that help much? Thanks in advance.

 

You shouldn't need to buy ground wires. But an after market flat braided (engine to chassis) ground wire isn't going to hurt!!
Engine to chassis wires.
Your Alt. is grounded though the bracket mount bolts and engine.
Both ends of your Neg. Bat. cable. Also check the length of the cable for internal corrosion. This is not uncommon and not very noticable.
Pos. Bat. cable and ends.
There is also a dedicated ground from the neg. bat. to the chassis or chassis terminal. Smaller wire that "Y's" off your neg. bat. wire. Check it and the terminal.

 

Great! Thanks for the advice, i'm planning to make my own ground wires, i was thinking an 8 gauge wire for the engine to chassis should be fine. I'm also going to check out the positive and negative battery cables for corrosion.

 

the battery ground to chasis is pretty small, yeah I know its only like 6" long but it doesnt hurt to run a heavier one. Especially if you have electronics that pull alot of current. I left the stock one and added a 4 gauge ground and noticed the voltage is more consistant.