When did NASCAR race cars start using dual ignitioins and why?

Question

what prompted NASCAR to allow the use of dual ignitions, do you know the year

Answer 1

I'm not sure of <when>, but <why> is in case of a failure of some sort to the initial igition. Just like how they do sometimes carry a backup battery if the original fails. A race or two has been won by a driver carrying a backup battery & switching to that after his 1st died.

Answer 2

I started to answer but after reading beth's there is no point as my answer would be redundant. Way to go beth. Another very impressive "car girl". That's something I love about NASCAR. Regularly being shown up by female fans.

Answer 3

Dual ignitions were used way back in the 70s, I am not aware of who or when they were first used. Rules were different back then. If there was no rule against it, you could do it.

Dual ignitions are used to give a complete back up system in event of an ignition failure. They are also used as a tuning aid or traction control aid by allowing the driver to switch to a different ignition timing setting.