How does one determine the correct size bearing you need to put in the case and around the crank. do you just take both measurements (case and crank) and then go off and get a bearing?

help.

Thanks

yes,
but also measure the width of the flange in the case
that holds the bearing at the fly wheel end.
This position is often machined true during the line boring process,
and so a bearing with a corresponding thicker flange will be needed.

So,
crank shaft jopurnal size,
crank case bearing bore size,
flange width of case at the #1 bearing bore,
are the measurements you need for ordering your main bearings.