340 Main Bearing Clearance

Question on choosing a Bore Gauge - I see shaft lengths varying from 6" to 10" . What length are you guys using
that avoids colliding with adjacent bearings/caps ?

You can do mains with a 6 inch shaft if you go from both ends. And I think if you have the 10 inch you still need to go through the rear to get 5, and maybe number 4 main. Also, if you look you can find a bore gauge that will go under 1 inch and up to a 6 inch bore. Might as well get a gauge you can use for wrist pins and lifter bores while your at it.