I wonder how many of the people commenting on this thread have actually made a living as an engine machinist? Being successful swapping main caps without line boring afterwards is about as likely as finding a chicken with lips. The only thing shims do on stovebolt main bearings is make slight changes of the vertical position of the bearing shells to adjust oil clearance. They do not alter the roundness of the block/cap relationship.

Bottom line- - - -the life of a set of main bearings after a main cap swap is done without line boring the engine can be measured in minutes!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!