Once upon a time, I was into IMCA racing.
One of the then rules was that your motor could not exceed 350 original cubic inches.
The claim was also less than $100.00.
I remember one guy that lucked upon (or so he thought) an unending supply for 348's.
The first one he put in his car blew twelve ways to Sunday in the first showing, due to the alcohol we ran and the inability of the motor to rev above 5500 rpm.
The second time around, he got one to last about 4 laps, but couldn't control the wheel spin, due to the massive torque and the weight of that boat anchor on the front.
He blew it up, too.
He tried a couple more but ended up using them in his old flatbed to haul his car around.
That was one piece of junk and I don't think GM was ever very proud of it.
As I remember, the two heads alone outweighed the 327/350 block.
“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.