Searching for 12v switched power after ditching ballast and installing aftermarket electronic ignition
With a Hyfire on a '73, it could be wired liked this with the 12 V switched on connected to any location on the J2 or J3 circuit - as long as they are still connected together. The J2 and J3 connect through the 1/2 ohm resistor. The 5 ohm resistor - if still used in '77 for the first gen. ECUs - will likely be too much resistance for the Mallory to turn on.
The 12 V switched wire simply triggers are relay inside the box. The power to run the box and coil comes from the heavy wire connected to the main battery feed. This could be at the starter relay junction (simplest) but will cause the ammeter to indicate slight battery charging. If the current draw is an amp or two you won't even see the needle move.
On a '76 as you can see in the previous post, the battery feed and alternator outputs join in the engine bay. The ammeter wires are tiny because its a remote shunt ammeter. The ammeter indicates flow based on the tiny amount of current running in parallel to the shunt. However the information displayed is the same. if you connect the Mallory's main feed at the starter relay junction, the ammeter will sense current going from the alternator to the battery - even though it doesn't actually go to the battery. Check the the instructions and if its under 5 amps it probbaly will barely move the needle. Or you could attach at the alternator's output stud.
With a Hyfire on a '73, it could be wired liked this with the 12 V switched on connected to any location on the J2 or J3 circuit - as long as they are still connected together. The J2 and J3 connect through the 1/2 ohm resistor. The 5 ohm resistor - if still used in '77 for the first gen. ECUs - will likely be too much resistance for the Mallory to turn on.
The 12 V switched wire simply triggers are relay inside the box. The power to run the box and coil comes from the heavy wire connected to the main battery feed. This could be at the starter relay junction (simplest) but will cause the ammeter to indicate slight battery charging. If the current draw is an amp or two you won't even see the needle move.
On a '76 as you can see in the previous post, the battery feed and alternator outputs join in the engine bay. The ammeter wires are tiny because its a remote shunt ammeter. The ammeter indicates flow based on the tiny amount of current running in parallel to the shunt. However the information displayed is the same. if you connect the Mallory's main feed at the starter relay junction, the ammeter will sense current going from the alternator to the battery - even though it doesn't actually go to the battery. Check the the instructions and if its under 5 amps it probbaly will barely move the needle. Or you could attach at the alternator's output stud.