<VV> starting problems

[Edmonds]

My '63 Monza 900 'vert has developed a problem which I've been unable to 
diagnose. When attempting to start the engine it begins firing as though 
starting but as soon as I let off the key it dies.  If I continue 
holding the key in start position the engine will rev up but as soon as 
I release the key it dies.
I've checked the fuel pump and it seems to be working o.k. and I've also 
checked the ignition and found nothing.  I have a suspision it is in the 
electrical system but have run out of ideas.
Any suggestions would be greatly appreciated.
Clyde