BoogieMan
Blues Junior
@BoogieMan
We can go into more detail elsewhere, but for now....
If C is a IV chord you're in the Key of G. The F# over the C chord becomes a #4, creating the C Lydian sound.
If C is a V chord you're in the Key of F. The Bb over the C chord becomes a b7, creating the C Mixolydian sound.
You can, of course, play the C Major pentatonic over a C Major chord, regardless of function..
In general, the Major scale played over each chord in the Key will produce a different "modal" sound.
Thanks Paleo. If it's OK with you I'll carry over to a new thread.