my 350 keeps dying

Hi all, I have a chev 350 in an aussie car(75 h.q 4 those who know it) and it has been in this car 4 about 18 months.. just recently as the engine gets over bout 2300 revs and has warmed up it just loses power completly and stops even at 80 mph, but if i restart the car it goes but as soon as it reachs 2300 rpm it dies again. I have pull the carb off and cleaned it(bot bowls where fuel and jets clean) and it is getting fuel but it still does it which makes me think it could be electrical any help would be great in this matter!
Cheers
Steve
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69 350 chev
elderbrook performer mainfold
holly 600
hei dizzy

what type of ignition do you have?
It sounds like the spark is cutting out at 2300.