How do you know it's the carb? Might be cam or heads?
I wouldn't run a 950 or 1050 on a 383. Not unless we're talking about 15:1 and a .750 cam with little chief heads.
At 8000 RPM and 100% VE, that motor is only going to use 887 CFM at most.
At 80% VE, it's only going to need 710 CFM.
The 4150 carb you have now is plenty.
From 6500 to 7000 the power flattens out and the torque drops. What cam/heads/intake are on it?