What a great tire the Pirelli P400 has been!

I put a set of Pirelli P400s (since discontinued) on my '77 B200 van back in 1996, and they've been really good tires. They have given me quite a run: they still look to be in good shape and have at least half their tread left. (They're 235/75-15s.) Even though I hate to do it because I'm a cheapskate, it's more than obvious that I need to replace them due to age. I would like to find a new tire of as high a quality as my old P400s were, but I'm clueless about the tire brands and models these days, and Pirelli doesn't seem to have nearly as big a dealer organization as it used to have when I bought my old tires, so maybe I need to change brands. Would anybody have suggestions about what a really nice, strong, smooth-running new tire would be for this vehicle, in a 235/75-15? Thanks a lot.