What's the compression ratio? A low compression can make an engine lazy.

The AFB is a great carb for the street. A Holley is a better carb for the track. You said this is a street car so stick with what you've got.

Lower rear gears would help. That A500 would pull a 3.91 nicely on the highway. Find out what the power band of the cam is supposed to be and get the rear gears that would put you above the low rpm point at 60 mph in OD.

I'd leave the converter alone with this being a street car.