[Cliff R]

I still remember being in the pits at Norwalk about 20 years ago and a guy pitted next to us "hit" his new 455 build with a shot of nitrous with disasterous results. He tore the engine down at the track since he was stuck there for the long weekend anyhow. Most of his new KB HT pistons were missing from the bores and piled up in the oil pan. They shattered like glass and left the rods and pins moving up and down in the bores void of any pistons on them.....NO THANKS!

I know that's an extreme scenario but it tells us that they have an elastic limit far below what you'd see from a decent forging, even the WAY too heavy TRW/Speed Pro forgings. Not a fan of those either because every set I've ran into ends up WAY to far down in the holes at TDC when I mocked them up required too much to be machined from the block to establish Zero Deck.

Anyhow, I've used Ross which are nice, and ICON, KB forgings. Since all my engines get forged rods and most will have the full floating option they fit the bill nicely. The modern alloys also allow for tight fitting compared to antiquated forgings from long ago. With a torque plate for final honing I set them at .002" here and have never had a single issue with that deal.

Even with all that said IF they made a nice flat top cast piston, even pressed pin I'd use them. Nearly all of my SBC builds get flat top cast pistons and they are fit really tight for minimal "rocking" in the bores, good ring seal and long life expectancy. The cast piston options for the 400's are absolutely pure bovine excrement and always have been. I still remember mocking up an engine I was hired to assemble decades ago using those pistons. They were WAY down in the holes at TDC and already taking over 15cc out of the squish area like using a dished piston. Team that up with a 4X or 6X-8 head in a 400 build and you'll have about as much compression as a Briggs and Stratton lawn mower engine, and left wondering why it doesn't idle or run for chit once placed in service......