I have them on my 58 vette
Thanks for that info Moms68. I have edited my original post to show 1956 through 1972 as the years that Guide T-3 headlamps were original equipment on GM cars. I'm basing this on the words of the 'expert' in the video attached here. Curious as to whether or not your '58 Corvette is set up for the scrutiny of NCRS judging?