69 340 problems

George, when you change your dist. try and see if the oil pump,dist.drive is sloppy with a straight blade screwdriver. It will only take a minute.
Are you sure the timing is right? It's easy to get it messed up.
When I rebuilt my 273,I had a rebuilt starter on my car and when I tried to start it , the same problem as you. Turns out the starter had a
dead short and was draing the battery very quickley and causing a very week spark. But when I turned the dist. by hand, the plugs had a big spark.