so you turn the key to run and the oil & gen lights in the speedo come on?
and then you turn the key to start and the engine cranks but doesnt start?
if you pull the coil wire off the center of the distributor, hold it close to ground and away from gas, and turn the engine over is there spark?
is the coil wired correctly?
are your grounds clean and tight? (battery, trans, ignition, etc)
is the battery holding a good 12.6v charge?
i dont know if this will help or not, but it's worth it to copy and give the harness the 'ole once over.
http://www.vintagebus.com/wiring/index.html