“That was one piece of junk and I don’t think GM was ever very proud of it.”
They can rev, but only after heroic (=very expensive) measures are taken. The stock pistons weighed over a kilogram each.
Another amazing thing about the small block was how flexible it was; it cost GM almost nothing to upsize it from the original 265 inches to 350 inches, but they could charge good money for bigger engines. The “400”, the biggest stock small-block, was a little different, in that it had siamesed cylinders with steam galleys and gasketing/sealing for the heads got dicey when “woken up”; it was also externally balanced. The head gasket/not much “meat” between the cylinders kept hot-rodders away from it. HOWEVER, a neat trick when I was a kid was to put a 400 crank/reciprocating parts in a 350 block, yielding 383 inches at stock bore (which GM never did, for some reason, possibly because of marketing confusion with the 396/402 big block). THAT was sturdy, and didn’t look different at first glance than any other small block. But, inches ruled the street, and it was a sleeper.
And, there were 400 engines with head gasket failures all over the junkyards.
Wow.
No wonder I saw one once blown with three pistons completely broken thru the side of the block.
I mean completely through.
One of them had broken loose at the wrist pin.
Kinda tells you that that was one hell of a rotating mass.