I Need /Help Adice, Ideas

[Already Gone]

I was driving home from a friends yesteday doing 65mph on the highway when all of a sudden the the truck lurched, hesitated and started missing. I looked at the gauges and they were all reading normal except the factory tach was flopping all the place going up to 5000rpm and then bouncing back to 0 and everywhere in between. I shut off the key pulled over and after I stopped tried to start the truck and it fired right up and ran normal at idle. I got out ,opened the hood and everything seemed normal under there too. When I put the truck in drive it started to buck some more and I feathered it and it got up to 50mph and it wouldn't go anymore. For the rest of the 5 mile drive home from there it bucked and hesitated and stalled about 10 or 15 times. Does anyone know what what might be wrong. I bought the truck in 2001 the way it is and I think it has the HEI ignition on it. This truck has ran perfect and I've never done anything to it in the 10,000 miles I've put on it since I bought it. In my limited knowledge I'm thinking a distributor/electrical problem. Anyone got any ideas on this? The pics were taken this morning.