6500 RPM 327, Hyper or Forged pistons?

[RichardSIA]

Trying to finish nailing down the parts for my 327 build since I'm about to buy an iron block.
Gave up on finding an "affordable" aluminum block, just cannt put $3K+ into just the block and will never go LS.
Already have a set of new .030 over Kieth Black Hyper pistons I got cheap.

Now wondering if I should go with a set of forged pistons instead?
I did attempt a forum search as I expect this has been discussed before, nothing came up for me.

Going into a '68 El Camino, might be more a Resto-Mod than Pro-Touring since I'm staying with 15" wheels and the Gen-1 engine - Muncie trans while trying to keep the "Old School" look.
It is getting a Jag IRS and rear disc brakes, might even get an overdrive down the road.

Daily driver but I am willing to let it warm up properly before taking off.
Will also probably see some fairly spirited driving, FOC track days just because, Virginia City Hill Climb, and maybe even the Silver State Challenge.



So far I've got the KB's, Eagle crank and rods, getting a 350 4-bolt block, have Brownsfield aluminum heads and Victor Jr. intake plus an aluminum flywheel.
Not at all interested in drag racing but would like to be able to hold the revs up between corners in the twisties rather than have to shift as often.
Want the engine to run well to 6500 rpm and live if I touch 7000.
Want to make about 400+ H.P. so the cam is also up for discussion.
Lopey idle is fine, even kind of desired, but not via the phoney cams ground for sound over performance.
Yes I know, we do not always get everything we want.

Bottom line for this discussion, would the KB's last decently long and not break?
I've been told they are "Better" than forged as they run tighter and do not rattle when cold.
It's really the high RPM durability that I have qualms about.

Semi-related question.
I have a virgin 327 block and crank that I cannot seem to get ANY money for.
Wondering if I would do better to assemble a short block to sell using the KB pistons?

[68Cuda440]

The hypers can run a tighter clearance because they expand less, this means less blow by, and less oil loss. They are not to be used with Nitrous and do not tolerate detonation as well as a forged. They are usually lighter. For most normal applications the hypers will be the better choice. Make sure your machinist either has worked with them or knows how to build for them.

[68Cuda440]

Look what I found:

https://en.wikipedia.org/wiki/Hypereutectic_piston

I did not see any inaccurate statements in the wiki post.

[RichardSIA]

Okay, I've never been too trusting of Wiki since anyone can edit.

No power adders and my home altitude is around 4700'.
I think my compression comes in at about 10:1, might be able to push it to 10.5:1 with a thin head gasket.

So if the pistons are good to go the next big decision becomes the cam and lifters.
Manual trans, Muncie, low but not super low gears.
I've considered solid lifters but hydraulic would be easier to live with.

I've had excellent luck with Rhoads lifters and "Too Much Cam" in the past.
Not sure how well Rhoads would live at high RPM, which will rarely be sustained for long.
Do plan an occasional track day so cannot skimp here.

[Skip Fix]

If using hypers be sure to go by the ring gap specs they are larger than forged. Not enough gap you wil break out the ring lands-knwo several guys that happened to short block built by reputable machine shops.