"The crank has been turned down to LS bearing specifications (to reduce surface area) and LS bearings are riding piggy-back on stock bearing shells"

I think I understand what's going on with this engine build except for the bearings.
This sounds to me like an LS bearing mounted inside the OEM shell.
Is this correct?
How do you keep it in place?
Wouldn't this be more prone to spinning a bearing?
Maybe I'm missing something?


Pete
64 Chevelle
61 C30 Panel truck