Do yourself a favor and toss the carb, edlebrock carbs are boat anchors you'll never get it right trust me.
Get yourself a 750 Holley double pumper, some 373 gears 411's would be better. I agree with the above that your heads are way to big for your low compression no gear having car, they are killing your bottom end. Big breathing heads and high lift cams and highway gears dont mix.
I wouldnt recomend monkeying with all that other stuff your friend suggested now I'm not saying that it would'nt help but NOTHING will help that car like some gears (373's or taller) and a good Holley carb will.
Goodluck >< Cp