Andre said most simply - contrast is sujective and there are no absolutes in good, high, low, or otherwise. It depends on the lighting, the surface textures, the deloper and development, paper - nearly the whole process, AND what you are trying to convey.
Here's another attachment where there is lots of variation in the surface texture and its tones. I overdid it a bit burning in above the engine to see how far I could push things (also excuse the quick scan dust specs). One reason B&W photogs like rocks so much is that there is a lot of small-sized contrast variations in the texture. Some call this macro contrast.
Mike, to answer your question, it sounds like you may be under developing. Try increasing your development time by at least 50% and see what happens. Then adjust up or down from there based upon the results. Some of us LF dudes develop by inspection so we look at it as its developing. Still manage to flub it too long or short once in a while.