Somewhat coincidentally I've been going through my loft today and came across a few old "Practical Wireless" from that time, and I remembered one project I did - electronic ignition for my dad's car! (used the points to control a transistor as switch, and then some serious voltage "enhancements" that pushed 450v into the coil. That was fun, and serious voltage. I remember it teaching me a lesson or two about respect for such things.
If you want a laugh, you can see that project here https://worldradiohistory.com/UK/Practical/Wireless/70s/PW-1972-06.pdf starting on p37 of the pdf: "it in no way alters the timing; thus in the unlikely event of a component failure, a quick rearrangement of the connecting leads taking less than thirty seconds enables the car ignition to be returned to normal and the journey resumed. " 
