A decent performance intake with a single 750 and nitrous will run circles around a tunnel ram/dual carb setup. If you have forged pistons adding 150 HP is easy and a reliable 200 HP kit is not out of the question. You'ld be fortunate to make 50 extra HP with a tunnel ram. Also, most tunnel rams for 4V Clevelands have runners that usually match the size of 4V heads. You'll lose lots of torque below 4500 or 5000 RPM. Nitrous does just the opposite. It adds gobs of torque, especially at lower RPM levels, say between 3000 and 4000 and makes your engine feel like a big block.