Hmm miketed by "can't keep it running" do you mean in revs up OK and stays running if you give it some gas or does it barely run overall? When the chain jumped on my old 318 it wouldn't even start and you could hear the starter "skipping" over cylinders where the valve timing was so far off it wasn't building compression.
When you installed that cam 6 months ago I'm assuming you had a double-roller timing set put in?
