1972 duster 340 fires up then dies and will not stay running

When I go to start my stock 340 it fires up then dies instantly. So far I’ve changed dist. Cap,rotor, pick up coil,plug wires,electronic box,voltage regulator. If I ride the starter car will start sometimes and then it begins to miss fire on the passenger side. Not sure what to look for here. Car is also getting lots of fuel. Could this be a ignition issue not sure what to look for here