Magging it is one thing. It won't tell you how thick the cylinder walls are. Chrysler says they are only good to a 4.00 bore but I had three of them sonic tested and all would go well over that. There may be some out there that won't.
The block I'm using now is at 4.04 but I didn't sonic it yet. If I go to a 4.125 bore with it I will check it.
