just wondering about how many cubic inches a 400 small block bored .040 would be? thanks in advance.

Don't really need another thread for this... But, here ya go.

o well you'll have that ,thanks anyway

Pi x (Bore/2)squared x stroke x number of cylinders

its 408 with standard 400 crank

Mathematically correct it should be called a 409. The common designation of408 probably gained popularity to keep from confusing it with the old 409 engines.

I doubt it's anything that sophisticated.

A 383 is about the only SBC that is commonly designated by its .030"-overbore displacement. And that's because it's a custom engine, not a standard GM configuration.