Don't bother- - - -the cylinder head design is so primitive that it can't benefit from those kinds of modifications. Dual carbs and headers are just eye candy on a stovebolt unless you do very radical modifications that make it unreliable for street use. Even then, the gains are pretty modest. A 261 is a much better starting point, and modify for torque, not horsepower. Even with a 261, get ready to spend a wheelbarrow full of money for pretty minimal improvements in performance.
Jerry
