Carb question

I am thinking there is a better carb for my ride. I currently have the holley street avenger 870 Vac secondaries carb. It has 82 and 87 jets with the standard pink secondary spring. The car runs good but wanted to know if there is possibly a better all around carb for performance and if possible to have both, gas economy as well. I currently get about 12 mpg highway if I take it easy. Normal driving gets more like 9-10 mpg. The engine is a 428 30 over bore. 600 lift 242/246 dur cam, headers, rpm manifold and alum heads.

Any and all opinions appreciated. I care more about performance but a few mpg's more would be helpful. Thanks in advance

1957 Fairlane Club Sedan
433 Cobra Jet-5 spd TKO600
3.70 Detroit true track