[Euro1320Racer]

More cubes is almost always good as long as you can get traction out of the suspension. E.g. my car would work worse with a 632 ci motor due to a lack of traction than it does with a little old 467 unless I backhalved the car. Other than that, a 383 is a good motor.
Do you know what your static compression is going to be with the Dart heads and this block? More torque will make whatever torque converter you have stall higher. Start off with the smaller 650 carb you mentioned earlier.