"LS-based" engines are on their 5th generation now, as they were introduced in 1997.
You commonly hear of the LS1, LS2, LS3, LS6, LSA, etc... When they came out in the Corvette, then the Camaros/Firebirds, those had an aluminum block and cylinder heads.
The trucks, vans, and SUVs had the LQ4, LQ9, LY6, and an entire host of other names. While some of them had aluminum blocks, the majority had cast iron blocks.
Bottom line, if you want to shave off 75 lbs and are willing to pay more, go for the aluminum block engines. If you don't care about the 75 lbs, and want to save a good bit of $$$, just go for the 'truck' blocks.
To me, the LS-based engines are much easier to get power from and don't have to work as hard as the old 350-style engines, plus they are much easier at the gas pump. You just have to determine what do you want in the long run? How much power do I really want? A 4.8L is cheap and can be made to be a super nice street engine all around (naturally aspirated, fuel injected, turbo, supercharger, whatever). If you want more, step into a 5.3L or a 6.0L.....or more!
