Lol dude.. the L is exactly the same as the E or X, they just have different VIDs and are binned differently. How good a given set of chips are depends solely on luck of the draw and their stepping.
For example, my 5420 C0 could do 430x7,5 even back when the Z7S was released, no Vcore nothing. Z7S gave them 1,14V Vcore under load, VID is 1,2V.
I couldn't go higher than 430 stable even with 6x mult, because they would need more VTT to go higher, which the Z7S still doesn't provide.
Any E0 step CPU will do FSB 440-450 on the Z7S regardless of what they are binned for.
The B1 step E5440 I had wouldn't go past FSB 370, go figure.
My X5450 which are also E0 can do a max of FSB 452 primestable (at any multiplier). Above that either the CPUs or mobo have reached their limit.