Would this set up be desireable in my 66 Cuda?

If you're starting out with a /6 swap, a lot of those extras will really get you started and might save money in the end. Even if the heads and cam aren't what you end up needing, you could swap those out (and sell the 340 heads) for things that would work better.

It being 'fast' enough is all in the eye of the beholder. It could be plenty for what you want, or it could be a dog - not sure on your perspective.