The importance of measuring bell housing runout.

I am the owner of an old Lakewood, I was in the ballpark, with filler insert for the small bearing retainer and I don't know how many rotatations and 2 different sets of offset dowels. Never thought of the block to bell being correct. Having said this, don't think that I would ever put some kind of tapered shim between the block and the bell if it was off. My brain has turned to jello in all of the planes possible from top to bottom. Not saying that it shouldn't be checked, but have no idea how how I or most people would ever correct it if it was off.