Doing a short block rebuild on a Gen 6 502. Should I pony up for the forged pistons or will the KB Hypereutectic pistons be OK? Supercharge at 5 psi, block temp is controlled to 120.

pony up for the forged. IMO, it should be a given with a blower.
I had a valve failure and it beat the heck out of my forged piston but didn't break it. from what I was told if I would have had the hypertech pistons it would have broken up the piston.
I still had to replace the piston, but it didn't gernade the rest of my engine.
DS

BD,

Hypereutectic pistons are cast pistons with some minor
improvements. They key word is cast and I would not
use them in a blower setup. If you bust one, there will
be a lot more than pistons to replace.

Spend the extra $ now and you won't have problems later.

Good luck.

OR

and 120 is way too cold to get your piston to wall clearences correct....

Most guys run there blower motors between 100-130 degrees,helps prevent detonation and allows you to run more boost on pump gas. Mine typically runs 100-120 degrees. All the old school motor tech I read when I was younger says this leads to accelerated cylinder wear,scuffing,etc BUT from personal experience I have not seen this in either motor I have had in my boat. After 170-180 hours of running these temps on my 502 block and 120 hours on my merlin 2 540 block there was no cylinder ridge and less than .0002 taper. If running a EFI motor just make sure your running a signal "conditioner" or a EFI program that recognizes this as fully warmed up so it doesn't stay in cold start mode and pour fuel to it which will cause it to run real rich and wash the cylinders,Smitty

Forged pistons. We have seen hypereutectic pistons shatter like glass. If there is anyway we can help you please let us know.

www.atecoengines.com

Forged it is, local builder recommends Manley. They swell less and can be set up a tad tighter. Something about the piston being machined differently at various points to accommodate the swell.

Actualy, forged pistons grow more than cast and hence cast pistons are generally run tighter than forged pistons. The important thing here is supercharging. Definitly use forged and also use a piston that is designed for supercharging. It will have thicker top sections over the top ring and it may be designed to give a lower compression ratio which is sometimes helpful when supercharging. Cast hypereutectic pistons are harder and more brittle and are not configured for supercharging, but they can work well in moderate compression normally aspirated motors especially where tighter clearances and a quieter motor is needed.

Ray @ Raylar

From my understanding the hypereutectic are regular cast pistons, with anther chemical mixed in with the aluminum as it is molten, it makes them a little stronger, but this was to have a middle ground between cast and forged, anything I have rebuilt I pony up for forged. Wiseco in My Harley and my 383 stroker was JE, both good brands.

I would advise JE forged.