Bell-housing alignment help
When it's line bored and honed, the crank centerline is maintained. At least if it's done properly. If it's done improperly than it might move the crank's CL up by a very small amount. I'd consider .002-.005" bad. So moving it .020" would really, really, REALLY be bad. Remember any changes ther affects the pistons' deck height, and the ability of any timing set to work properly. So it's a big deal and nobody moves it intentionally.