you would need to convert to mass air for a cam swap..not required for a head/bolton/intake swap...the conversion would require a mass air harness,ECU and maf sensor. Gears, convertor, shiftkits, etc will not effect your current speed density system and will work fine.
first of all if your going from stock. you mean 55mm to 70mm. to big for your stock heads and intake. go with a 65mm. if you already have one cool. but i doubt you see any horsepower. since you still have the same heads and restrictive intake. maybe 5-8hp.