Well, I think it depends on what event causes you to bug. If an EMP goes off, most people aren't bugging anywhere in a car. Only pre-1978-ish vehicles will run, and then only maybe. Even in the nuclear atmospheric testing of the 1950's, several of those pre solid-state electronic cars were disabled. The Compton Effect is the real deal, and allows some horribly primitive enemies a way to set us waaaaaaaaaayyyyyyyyyy back. Congress completed a very detailed study of what an EMP would do to us. They estimate that within a year of being hit, over 90% of the population would die. This report would have made waves, but was released on the morning of 9/11/01. Kind of got lost in the shuffle, but it should still all be on our minds as we prep.
A great book on the subject is "One Second After" by William Forstchen.
I am not positive on this but if I understand right all you have to do is replace the points and condenser and everything before 82 should work again