Hemi engine swap proper ignition switch

[Rebelrouser]

Ok I am finishing up the wiring on a hemi swap that somebody else started 3 years ago. In the instructions the supplier of the harness says that old style mopar ignition switches will not work, because of the drop in voltage as you turn the key, they recommend using a push button switch for the starter and not use the stock switch too activate the starter. You guys that have done the swap, what did you use? Stock ignition switch or something else?

 

[pnora]

Stock switch. Depending on the ignition system you may have to tie the start and crank ignition feeds together and eliminate the ballast.

 

[70chall440]

The start side of the ignition switch (meaning that part which activates your starter) has nothing to do with G3 hemi, its just a switch that provides power to a relay/solenoid which in turn activates the starter motor. That action is the same regardless of what engine is in the car.

The part that most have an issue with is the EFI and/or upgraded ignition side of things. For these situations you need power in both the crank and run positions whereas in the old school/original set up this was/is not the case.

The ignition switch has a ign 1 and a ign 2 (one has is typically a blue wire and the other a brown wire). In the stock configuration when you crank the engine the stock switch and commensurate wiring (ballast resistor, etc) reduce the amount of power going to the rest of the car allowing most of the available power to be applied to the starter and ignition system to spin the engine as quick as possible and to provide the hottest flame possible.

The stock switch is still your best most reliable system, all you usually have to do is to make sure that you have power to the system in both the ign 1 and 2 positions.

 

[Sixpactogo]

I tied Ignition 1 & 2 together on my 68 Charger back in 2015 when I upgraded my car to a 6.1. It worked most of the time but about the time I thought it was good to go, it would act up on me. No idea why but it would start and run but not properly. I would shut it down and restart and it would run good again. Chris at Hotwire.com told me to add a push button in place of the ignition switch. I purchased a push button switch from NAPA and it has been working properly since. No idea why there was a problem with the factory set up since the Hemi didn't like a break in continuity between start and run. As far as I know when you tie the start and run together, there should be no break in continuity. My meter couldn't see a break but the Hemi didn't like it for some reason. Good Luck