426 inch+ small blocks

But the BB motors are larger, the height, width. So back in the old days, the factory just built larger engine blocks for just a 1/4 more stroke...like its nothing. Even Mopar made the crank mains larger going up a bit in stroke in the 360 motors. What would have Mopar done to run a 4 inch stroke, nothing, I highly doubt it.

To me 10,000 miles isn't much, I sure hope any motor will last that long. Back when I was in high school and the old 60's cars were 10 years old, we all had them running pretty good with 100,000 plus miles on them. Those motors lasted a nice long time back then.

Nope, I'm not rich enough to run back to back tests but common sense tells me the factory's did not make the larger CI blocks much larger than the SB for no good reason. Long stroke engines were never thought of being for high rpm's. The Hemi, the 440 all had 3.75 stroke, why? Few engines had 4 inch stroke, just GM's and one Ford, the 400 ci..Fords 429 which was bad ***, had just a 3.59 stroke. The Ford 400 ci was never thought of as a HP engine. They were for trucks and vans, not sport cars.