340 or 408?

Newbomb Turk said
How was it 427 inches with a 4 inch stroke?

The 396 and 427 have the same stroke and different bore sizes.

The 427 and 454 have the same bore size and different strokes.

If it’s a 427 it has a 3.76 stroke.

Well, no, it was a 4" stroke. This is the Small Block LS7, not the old BBC 427. That's why I mentioned the fuel cut-off speed of 7200 rpm. You are correct the old BBC 427 had the shorter stroke. The Small Block bore spacing did not allow for that old BBC bore size!