You might want to double check your intake manifold. If it's an Offy that's the only designation it will show on the casting. If it says "6=8" that's a trademark for a Clifford, which is a different animal. Rule of thumb, the Clifford does better for more modified high RPM slants, an Offy is better on the street. It might make a difference which one you have as pertains to your goals for the car.
And if you're looking to do a mild improvement on your slant, a Super Six setup is a dandy way to go.