Lycoming O-320 question (in a C-172)

[Steve]

I noticed today that the engine in the 172 I instruct in was originally a O-320 E2D and was replaced with a E2H model. Anyone know what the difference is between these two?

 

[VNugget]

I noticed today that the engine in the 172 I instruct in was originally a O-320 E2D and was replaced with a E2H model. Anyone know what the difference is between these two?

http://www.prime-mover.org/Engines/Lycoming/Lyc_Cert_list.html

O-320-E2H: Same as -E2D but equipped with S4LN-20 and -21 Mags.