318 dodge dart stumbles 5000rpm

Badart, what do you mean "chrome box"
My 318 with stock cam, heads and carb. Dual exhaust and rebuilt the stock carb a few months back. The car bogs down and feels like a total loss of power. I let of the gas a little and car reacts again and starts driving normally. I don't know the rpm as I don't have a tach. If I ease into the throttle it'll accelerate past 70. It's the sudden mash like from 1/5 pedal to 4/5 pedal where it acts up.

Any ideas?