Idle control prob.
 

Not a major problem, but annoying none the less...

My 78 4.5 with K-Jet, idles in drive at about 700-750, which from what I read is normal, however my neutral idle is around 1000-1100 RPM I tried turning the idle down but the screw is all the way in (CW) Is my Idle Air valve stuck or leaking? can it be removed and bathed in carb cleaner?

I'll bet you've got some air leaks somewhere else that is causing the idle to be high. Try spraying a little carb cleaner or starting fluid around the injector seals and towards the ring seals between the upper and lower manifolds to see if you can detect a leak that way. My '79 also has that idle valve, and it is a pretty positive device.