Jerry,
I remember the Sears Diehard "forever" batteries in late-60s/early-70s, when my Suburban was my main vehicle. I do recall them having a 6v version, but I had converted my 1954 Suburban to 12v when I blew a 235 and installed a 12v 1960 261.
I could not afford the Diehard, but if I had bought one, I wonder if the lifetime warranty would still be good (good for the life of the vehicle).
