600 vs 750 Holley

Right now I have a well tuned 600 vac sec Holley on my 360,I now have the 3310-2 750 vac sec ready for rebuild.What difference in performance can I expect going from the 600 to the 750,I know my gas mileage will be different tho.Share your opinions please.My build is 360 20 over,202 J heads rebuilt no porting,LD340 intake,MP cam 284-474, headers,2400 stall, 323 gear,727 with Trans go 2 shift kit.