Classic/Antique Car Repair: 1972 Dodge Dart, dodge dart, 225 slant 6

Question
My dodge has a 225 slant 6 engine with a rebuild carb.
It refuses to start after it warms up and is driven fro about one half hour, why?
I put an electronic ignition in it. Also, I put an inline metering device, no change after each change. It gets plenty of fuel but still refuses to start until it has sat for about 30 minutes.
Also, I replaced the inline fuel filter.
This dart was made in Canada and has only 123k mile on the original engine

Answer
James ;
hi I have seen this with some chevys , the starter is old and the fields are old and it will not turn over due to the fields, can you try to replace the selonoid, or both starter and see id if helps touy, as I have had it happem to my 350 nova.  so  its all I can think of. but check all battery conectiond are clean even block