1968 Barracuda fb 318 4spd

I coulnt wait to get her setting back on its susspention. It seams to take me for ever to get all my front end parts togeather. Ive enjoyed cleaning parts and painting them, kinda theraputic. I think I put the frontend togeather 4 times before I had it all figured out, being apart for solong.
I have the original 318. 30 over with a mild cam. I also have a set of 340 X heads. I will be useing a local machine shop who specilizes in mopar race engins
can anyone tell me from there experiance what it might take to get about 400 hp or more out of my engine.