Google "I beams" and "H beams" to visually see the difference. I'd assume H beams would be stronger, but again not really a necessity unless ur goin all out and spendin a **** load on ya motor and it's gonna make serious power.
The different pistons are mainly the alloy they're made from and the way they are made. Plain old cast pistons are just an alloy, hypereutectic pistons are also cast but have silicone in the alloy as well which I think changes the expansion rate of the alloy (ya can get a few sorts of these I think which vary how much silicone and other additives go into the alloy). The next step is normally forged, which is alloy, but instead of cast, it's stamped which compresses the alloy and makes it alot stronger, then I guess after forgies ya'd get billet pistons, which are a tad extreme.
If it's for a tough streeter, I'd just get a scat/eagle kit with hypereutectic flat tops. The reason there's a few different sorts which expand/contract differently is coz if u use normal pistons with forced induction, ya get a shitload of heat and if it expands to much it's gonna try and sieze up with it expanding into the bore and you'll end up breaking sumfin. Not just forced induction, but alot of revs will do it too. So I guess u either give the pistons more bore clearance so they have plently of room to expand (which will result in less compression), or u choose different pistons with a different alloy which doesn't expand as much.
All the technical **** is new to me, I ain't no mechanic and I haven't really played with that stuff too much, so not 100% sure. I only know a bit about it from an engine building DVD I bought only a week ago haha! If ya don't mind playing with motors ya should look into getting it too.
Power Building Videos - Power Pack - Performance Carbs - Rotating Assemblies - Heads,Porting & Valve Trains, Superchargers & Nitrous Oxide
