John Shriver , Jan 03, 2006; 07:18 a.m.
The folks who develop old film on the Classic Cameras forum here have found Kodak's HC-110 to be a good choice of developer. A little better at keeping fog down. However, I've also had fine results with D-76.
Certainly, you could increase the development time a little. But, it will only make the fog worse. Expect a low contrast negative, no matter what you do.
There was no film more designed for keeping properties, both unexposed, and of the latent image, than Verichrome Pan.