I know this is probably impossible to diagnose, but a friend of mine has the above car. Occasionally it will start normally and run OK. Try it again a few minutes later and it won't start even after repeated attempts. Come back to it 30 minutes or an hour later and it will start again normally etc. and so on. The engine is twin cam but using single point injection. All the following check out OK: New battery fully charged. Fuel at carburettor. Plugs OK and good spark. Distributor cap not cracked and central spring loaded carbon OK. I've re-seated all ignition/coil plugs and terminals.
Is there anything else I should be checking?
Many thanks to anyone who may respond.