Only a 770cfm carb? Man you are choking that thing badly! A healthy 302 can use a 750 cfm carb and still be VERY streetable. That engine needs at least a 850cfm carb. I bet if you dyno the car with that 770 cfm carb and then swap out to a 850cfm carb you would pick up at least 40whp. Assuming you do not use the current air filter assembly.