I like this setup better:
http://www.turnswitch.com/Turnsignal.htm I am using this for my third antique car turn signal kit. You can use a momentary micro-switch for the lever.
Turn Signal Control w/o switch - $109.95 and a momentary switch is $5. Similar price and much better functionality.
* Operates with 6 or 12 volts, Positive or Negative Ground.
* Easy installation with included instructions, wiring diagrams and terminal labels on control.
* Fail safes with brake and park lights still functional even with blown turn signal control fuse.
* Shares front Park or Fog lights for front turn signals.
* Flash rate independent of lamp load. Will flash LED lamps or incandesent lamps at the same rate.
* Controller can use any momentary switches to trigger turn function.
* 4-way Hazzard function.
* Quick disconnect of control box for easy service. No longer requires removal of each wire.
I like this better than the black box sold by the Model A vendors as well(I have two of them) as they are also self canceling by time and cheaper too.
I am not connected with this outfit, it is IMHO the best system out there and thought someone would like to know!