Carb questions

[1980convertible]

Now I have been looking a little into my carb situation and I want something that is quick off the line and gets good mileage with good power after 2500rpm. Now I guess I am asking for a little much but I was wondering if a Holley 2 barrel 500 and an aluminum intake manifold will do the trick. On my 1980 convertible I had an Edelbrock 650 on top of a 4.2L 255 and that thing tended to eat a little too much out of the pocket book. Any ideas that aren't too expensive would be of great help.