[MikeK]

To use the Acc position on the switch requires wiring the Model A differently.

A replacement switch with an Acc terminal works like this- The BAT terminal connects to BOTH the coil and Acc terminal when turned to the on or run position. In the Acc position BAT is connected to only Acc.

In an unmodified A the battery goes to the coil first, then from the coil to the Popout switch and then to the dizzy with the points and condenser.

Your replacement switch will work if you connect the wire from the coil to the switch BAT terminal and then the "Coil" terminal on the switch to the Dizzy. BUT you cannot use the Acc terminal if wired that way, as any accessory you connect to it will be in series with the coil, not directly connected to the battery.

To also have use of the Acc terminal you must first run from the battery /power source to the switch BAT, then the switch 'Coil' to the side of the coil the original feed went to, then from the other side of the coil that originally went to the pop-out you need to loop through the terminal box with no switch connection and go directly to the Dizzy.

Curious as to why you refer to this as an "upgrade". You lose the originality of the vehicle, and can no longer turn the car on, remove the keys, and later shut it of and lock the ignition simply by pushing the 'popout' back in. Now you are a slave to dangling keys. Although you gain the Acc terminal you also lose the original wiring scheme and wiring harness connections. Not good unless you are experienced at vehicle electrical systems as the original wiring diagram in the instruction book is now useless to the average guy for running down a problem. To me it is the opposite, a downgrade that also requires other modifications.