Non-starting... may or may not be electrics

[Risocco]

I think carb cars just have a mechanical pump, turned by the engine.

Bingo. From the crank. Hence carb'd cars rule

Alex

[Nate]

mechanical pump only on the carbs as standard, however some people do fit electric pumps so you should check ;)

mechanical pump can fail, or weaken with age. check that it is delivering a healthy supply of fuel to the carb. if you fit a clear plastic filter in line, you'll be able to see the fuel pumping thru it.

check the main earth from the gearbox to the battery. make sure this is clean and the cable is in good condition

similarly if this car has the earth strap from the bulkhead to the rocker cover make sure this is in good order.

does this car have electronic ignition? if so, look for a possible hall sender or ignition amp fault (swapping with known good from another running car is easy way)

if it hasn't, check the contact points are clean and adjusted correctly

[the edmundator]

ignition amp fault

This appears to be the daddy. Just had a very thorough RAC man out who checked it all over and adjusted my distributor timing a bit (he was amazed I'd got it anywhere near right by just sticking the new dizzy in place). The car runs really nicely but then stalls and loses any spark.

He seemed pretty sure this is the ignition amplifier building up too much resistance and warming up, so that it stops working until it's cooled down sufficiently. If I go out to start the car in about an hour it will probably work... for about 5 mins.