HE means LT-1.
The LS-1 was the all aluminum motor that was created for the C-5 Corvette in 1997 (or was it '96).
The LS-1 is bascially an all aluminum LT-1 with some other changes.
The LT-1 differs from a regular small block because it has reverse flow cooling (the cold coolant from radiator goes to the heads first, then the block). This allows for higher compression ratio, better economy, and more power.
Jay
