It's all about tuning.

A combo like that should have plenty of low end torque.

I had a 318 with 360 heads, .480 cam, headers, M1 single plane and 750 3310 Holley. I would boil the tires from a stop and bark 2nd hard even with really low compression and 3.23 gears.

Did you degree in the cam or slap it in there? Could be part of the problem..

Sounds like you're about ready to tear into the distributor. Make sure the weights are clean and function properly. A cheaper set of springs is the Mr. Gasket #925B springs. Usually go for $11.00.

Carbs can be picky. We had a brand new 750 3310 that some of the plating came off of and got lodged. Truck ran fine until we put about 500 miles on it then started acting up. Dipped it, blew out all the passages and it worked perfect.