I've been at this for almost a week on and off with not much luck.

Right now the car starts after a lot of cranks and the power freaking out in the cab. I know I've got to be doing something wrong.

I've scoured the existing threads hopefully someone can lead me in the right direction. The wiring is messy and temporary (I'm going to shell out for a proper sealed box and remote off switch once I have stuff working the simple way)

The battery is an Optima red top, its fully charged off a battery charger.

The battery has two grounds:
0g wire to a threaded spot in the rear
4g wire to stock negative battery terminal location under hood

Positive power is run to the stock positive battery terminal location using a 0g cable.

In addition to the stock wiring a 4g cable is run from the stock positive battery terminal to the starter.

There is an extra ground under hood from the stock negative battery terminal location to the body.

I just want the car to start smoothly and reliably. WTF am I doing wrong?

Thanks in advance.

Battery

Rear Battery Ground

Front Wiring

 

With my 68 I moved the battery to the trunk (its a show car) and only have one wire (replacing the normal red one) just longer to the back and only have one neg to the frame. try rerunning a ground to just the frame (make sure its ONLY metal). We also had the cut off switch... we ran the red to that then to everything else, use a voltage meter and check and see if your getting your volts everywhere also. GL!

 

Also check for a voltage drop across the different connections while cranking the motor or disconnect the battery and measure the resistance on each connection. I expect you have a high resistant connection some were. If I was guessing it is probably were you connected under the hood.

Did you crimp and solder the terminal end connections? I will always do both on battery cables.

Hope this helps.

 

I've got a multimeter, how do I measure resistance over a conection?

 

resistance wont tell you anything. one strand of copper wire will give you good continuity. .

you need to set the meter on volts DC, and put one lead at the positive battery, and the other lead at the positive terminal in the engine compartment, then check the voltage cranking, that is your voltage drop, it should be under .5v DC, most manufacturers say less then .25vdc