Have 65 nova with 283 cu.in.It has an aluminum intake and Summit carb with a mild cam. It starts great and idles at 1000 rpm. Timing is at 4 degrees btdc with no vacuum advance.As soon as you get stopped at a traffic light or stop sign the idle drops to 350-400 rpm and engine dies. It will then start right up.It has new plug wires,plugs with HEI distributor. Not sure where to look next. Any ideas will help.