Best 318/x-head /hyd cam combo

Ol'Dodge, that's what I would do.
If you want to use the smaller Comp Cam, the stock converter, intake and the rest of the combo will work well togther. The gear is way tall for the engine combo. And that would be the thing to change.

Low compression is not the end of the world. Better to have a good flowing head and low compression rather than the reverse.