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lighter crank
wind up quicker
easier on bottom end webbing
less stress on cylinder walls due to less stroke.
less torque to help with traction up off corner in slick


I believe most...

I could have gotten bad info on the school bus part.
that 509 seems to ring a bell on it being the better blocks.

If you Can find the high nickel 400 blocks they are extremely strong (for a stock 400)
I think they were in school buses, etc.
Someone told me they were a Mexican casting, but dunno if that is true...