Pirelli has discontinued the P4000 in 14 inch size, for some reason and I suspect they did the same with the 13 inch tires. I really like the way Pirellis handle, tire wear is not as good as Michelins, and I particularly dislike Michelins, their pricing has gotten way out of line and the tires are hard and noisy. I saw a set of Pirelli P4000 13-inch tires at a wrecking yard, I was ready to buy them because they were hardly used, but when I saw they were 13 inchers I was disappointed. Too bad your not closer to the left coast.
Dieseldiehard
1971 220 (gas) 4-spd manual 104041
1979 300TD w/ ’85 turbo engine 289560
1983 300D 237490
1985 300TD 206150