Here are a couple of holley reference sites so you can determine what your carb was out of the box.
http://www.holley.com/HiOctn/ProdLine/CarbList.pdf
http://www.mortec.com/carbs.htm
Here are some sample 750s and you can see how they vary from model to model
3124 750 (F)70,(R)76 8.5,8.5 4150
3247 750 (F)70,(R)76 8.5,8.5 4150
4779 750 (F)75,(R)76 8.5 4150
4779-1 750 (F)70,(R)80 8.5 4150
4779-2 750 (F)70,(R)80 6.5 4150
4779-3 750 (F)70,(R)73 6.5 4150
4779-4 750 (F)70,(R)80 6.5 4150
4779-5 750 (F)70,(R)80 6.5 4150
4779-6 750 (F)71,(R)80 6.5 4150
6109 750 (F)75,(R)76 8.5 4150
6709 750 (F)652,(R)76 6.5,3.5 4150
8156 750 (F)70,(R)83 6.5 4150
80186 750 (F)70,(R)70 6.5,6.5 4500HP
80186-1 750 (F)70,(R)70 6.5,6.5 4500
80378 750 (F)59,(R)72 2.5,2.5 4150
80378-1 750 (F)56,(R)73 2.5,2.5 4150
80528 750 (F)72,(R)84 6.5 4150HP
80529 750 (F)72,(R)84 6.5 4150HP
84779 750 (F)70,(R)73 6.5 4150
I would go back to default settings and then if you still have a bee in your bonnet, try going up and down 1-2 and see how it feels. You'll probably need a dyno or race track to really dial it in. If the carb is right for you engine, it should be pretty close out of the box.
hope this helps
Andy