1971 Duster 360/727

So I decided to switch out my carb for a new street demon instead.
Got recommended the 625 instead of 750.

Installation was a breeze and it fired up instantly, ran really smooth.
Took it for a drive and when I give it gas it just rumbles and shakes the whole car, also feels like a turd.
It runs much cooler though and much better in low rpms.

Anyone with experience with these demon carbs who can give some advice? I tried adjusting the mixture screws but didnt really do much difference.

Cheers