My recommendation is the same as the others, check the solenoid and the fuseable links. My cutlass was going down the road one night and the lights and the car shut off, a second later back on, I drove back home 2 miles with it doing this, the power wire from the battery to the solenoid was loose.
Another time on a 79 camaro Z28, the excessively hot headers melted the solenoid internally, you`d go to start it and let off the key and the starter kept going. Then you`d shut it off and try and restart then nothing. The smaller ignition wire`s internal post was almost completely melted away which caused this gremlin. Last but not least I changed the valve covers on a 79 chevy malibu, I slid the valve cover forward which made contact with the wire going to the back of the alternator, causing a instant short and sparks flew, it blew the fusable links.