Advice needed: Budget rebuild

I have a 69 Barracuda that I recently acquired and the motor is a little tired (318). I have some J heads laying around (2 sets) as well as a 4bbl performer Eddy or even a 4bbl 340 stocker manifold and a Holley carb (can't remember what cfm it is). Plus, I have some headers of unknown make and origin that COULD be used (but not necessarily) - although I am not even sure if they fit that car.

I would love to use all these parts to do a budget build for that car. My concern is that the J heads will lower the compression ratio a good bit. Should I get them milled? I also wonder if they would work better if bought a cast stoker kit - this car won't make enough HP to work about getting forged.

And, which would be better for the intake? The Eddy Performer or the cast iron 340 intake? I think I need about a 600 cfm carb for this type setup so I will check on that Holley (I want to say its a 650).

What say you?