Are the KB and Speed Pro hypers stronger than a BONE STOCK
LS cast aluminum utectic piston?

Or does the factory GMs kick the aftermarkets bootie??

I’m trying not to waste 4-$700 in my budget mopar build.

Wiseco Street Protru is forged light weight 440 piston for street builds comes with rings and is BY Far the best value out there at around $450 a set that is less than KB cast junkers that weigh a ton so no need to compare heavy cast stuff

So yourcalling factory LS pistons cast junk?
Maybe thise that come in a gen 3 hemi are but what makes a LS piston better than a KB or SP hyper?

It always amazes me that everyone calls KB hypers junk. Hyperutectic pistons are stronger than any cast or forged piston.

Hyperutectic pistons are stronger than any cast or forged piston.

I dont think thats being disputed, just the proper application for certain pistons is.

Right on EV2Bird. The application is critical. United Engine & Machine who manufactures KB hypereutectic pistons and Icon forged pistons has an application chart in relation to silicon content. I have it but don't know how to load it on here. It may be on their web site by now. UEM was the innovators of the KB hypereutectic pistons. Their primary purpose is for performance street use. But can be used in race applications of limited rpm motors. Just remember, on any hypereutectic piston the ring end gaps are very critical. Follow the directions that come with the pistons.

I would use a little extra gap so .032 to .034
Street supercharged on e85

https://www.uempistons.com/installation_instructions/kb_installation.pdf

In a 440 application the KB is heavy as an anvil That is not good

Comparing apple's to apples hypereutectic pistons are more brittle then most forged pistons, which is reason to be leery in a boosted application. They won't be as forgiving on the tuneup...but of course can work if you're careful.

I think people get confused when we're talking about materials sometimes. A modern cast hypereutectic piston isn't in the same universe with an old cast 440 piston. A pro tru piston uses 4032 material which also has high silicon content of 12-13%, making it borderline hypereutectic. Also wouldn't be my first choice for a boosted motor.

Most race pistons are 2618 material which is less brittle and will tolerate detonation better.

I've seen plenty of cast pistons explode like a hand grenade into tiny little pieces in the bottom of the oil pan when abused when the same amount of abuse to a forged piston didn't do that
Have you seen a cast piston come out of a motor that broke off one of the heads of valve with the valve stem or valve head stuck into the piston still?
I haven't, but I do have several forged piston in my broken race part boxes that did
Build the motor for the intended application and use the parts that you think will live and work the best

Yeah I was confused by this statement myself? Typo maybe?

I agree with Cab as I have all forged internals in my engine. I run Mahle 4032 pistons. Here is an article I found explaining 4032 vs. 2816 alloy pistons
https://www.google.com/amp/www.hotrod.com/articles/mopp-081008-mahle-piston-alloy-comparison/amp/

Hypers might be stronger hardness wise. But they are more brittle, they can shatter like glass with serious detonation or some kind of impact at rpm be it valve or some other kind of contact.

APPLICATION. I guess some don't get it, the application is the answer. All pistons are designed and engineered for different applications. Hypers were designed for street performance engines. Will withstand the heat and abuse of street use. Require less clearance, therefore are quieter. Plus high wear resistance = more street miles.
If a little boost is used, and is still primarily a street engine. Try the 4032 alloy a little more ductile than hyper but a forging.
For racing a 2618 alloy is offered. Hi ductility, requires more clearance because it has a higher expansion rate. These pistons can be machined for your application. Icon now offers an Extreme duty 2618 piston. Which are being run by Jeff Lutz.

kb 440 hyper pistons are lighter than factory cast or forged replacements.

I've beat the snot out of kb hypers without issue, but I follow the instructions to the letter.

anybody who has taken a serious look at the kb hyper vs the factory autothermic can see the hyper is much sturdier.

I use the 2618's in one care and kb hypers in the other without any problems with either. I think the big issues with hypers are idiots who won't follow the instructions and the same idiots who use a cast piston when a forged is the appropriate choice. some folks work at turning the purse into a sows ear.