What happens if....

this thing is oooollldddd its got a gold looking color. well heres the problem. when i first put it on the new engine it would idle but as soon as i put it in gear and put a load on it it would start running like crap, so my dad told me to put bigger jets in it and i did. that made it run pretty good just cruising around. now if i try to get on it and it gets around 3500-4000 RPMs it just starts doing the same sputtering crap.. its really annoying cause I know the car would run better than this. So I was wondering if i put even bigger jets in would that help the problem or is that even the problem? Its using the stock electronic ignition box and an OEM replacement coil. The intake is a edelbrock performer series. And the carb is...List 7006-2 2016 Those are the numbers on the choke housing? I think thats what its called. I did take it all apart and clean it all. With a new rebuild kit. So it has a new power valve, new gaskets, new everything. But it still runs like a POS. What am I doing wrong here? I am not really too excited about putting a double pumper on there, I do have to drive this thing everyday. And here is some more info if this helps. It is the stock distributer it has been rebuilt new pick up coil with the air gap set to the proper .004 I believe it was I cant remember exactly with the brass feeler gauge. New cap (its tan color real heavy piece, my dad said that its a really good cap) new rotor, 8MM plug wires (nothing performance there...just plug wires) and Bosch Platinum Spark Plugs. Exhaust is...Summit brand headers, 2 1/2" to flowmasters then turndowns before the rear end housing. the exhaust passages that flow from the head through the intake (im assuming to warm the carb) have been blocked off...umm am I not really sure what the timing is set at, my dad did that.

I hope this is enough info to help...