carb problems.

[coffinator]

I have a Zenith 34 NDIX off a porsche. Its been on my manx sr for years. I now need it to be rebuilt and the local carb shon wont do it because it in an import. I know porsche is going to charge an arm and a leg if they can even do it. What size carb should I run? I have a 1989cc type one. everything else is stock. I want to run duals but dad says no. Sence he is the one paying for it what he says goes. I was thinking about dual 34pic single barrels. I want it to have as much Horsepower as it did but not suck gas. I am fixing the car so I can drive it to and from school and get better than 18 mpg. All help and comments welcome.

Thanks,
mike