ok, i always figured hyper is the way to go, within a couple of bucks and has better heat charateristics, but summit has a deal on a rebuild kit with all name brand parts for $285 but comes with keith black cast pistons, the other kit i like is 220 and comes with all summit parts including summit brand hypers

i could piece together a kit for over 300 and get best of both worlds

 

And your question is.......

 

which is the best option? is cast really worse than hyper or is the difference minuscule?

 

Stregnth is really minimal, power adders or high RPM will kill both pretty easily.

Though the KB's are really just repops of the old style GM pistons (pre LTX) while many newer pistons have modern features like short skirts etc.

Many hyper pistons are repops of the LT1 OE piston and thats not a bad thing.

Hypers have a reputation for being brittle compared to regular cast but like I said it's not enough to wory about cause if you do need to wory about breaking pistons neither should be on your list.

In the Mazda world it's become popular to swap the N/A 2.2L F2 short block in place of the original block in the turbo MX6,626 and Ford Probe fpr a few points extra comp.

The original turbo pistons are hyper while the NA pistons are cast. except for the high comp cast being worth an extra 10-15 HP at stock boost they seem to perform the same when beat on, neither fails significantly before the other.

 

exactly what i was looking for! thanks!!!

its mostly going to be a cruiser motor for my dad, so rarely beat on.... both pistons are flat top with 4 valve reliefs (5-6cc) so neither are the stock dished pistons from sbcs unless you mean the overall design

these are the pistons in question
http://www.summitracing.com/parts/UEM-1436-040/
http://www.summitracing.com/parts/SUM-17350-40/

 

Yeah the KB's are stock replacement flat tops essentialy, your application may have come with dished pistons but they are essentialy the same material and design with the exception of the dish.

For your app they could be considered an upgrade but for others they are simply replacements.

 

i was just reading that silv-o-lites were hypers too but not sure...

would the KBs be ok for my NA motor, should be making ~400fhp

 

I'd go with the hypers.

Actually, I'd probably go with a forged TRW piston, like a 2256 which has the same weight as a cast stocker. I only use hyper pistons on stock rebuilds. I throw cast pistons in the garbage.


Anything can make 400hp, but will it stay together..

-- Joe