I had 6TL's in my CUCV and I was not happy with them. They leaked acid all over the place and made cleanup and painting of the fender and battery trays a big job. I think I got two years out of them. I put in group 31's from the local auto parts store and the Blazer starts better than ever.
I have "blem" car batteries in the deuce, and even these batteries crank better than the 6TL's.
6LT's have some interesting features, like extra rugged construction and the ability to be completely submerged, but for their size, they don't have as many cold cranking amps as you would think.