My dad put them in my 69 Mach1 when it was still his in 72, and they are still in there. Man, would those things light up the reflectors on the double yellows. You can hold your hand 3 feet out and feel the heat. His buddy at work put a set in his 67 Goat, and the GM alternator would not keep up with them, ran the battery dead if he ran them for long