"But for $200, I think I like the piece of mind of switching to bearing shells. we'll see."
I just went thru this ordeal with 2 engines trying to decide which one would be the best candidate to expend work on. Mine are 235's of 51-52' vintage, but the big end rod bores are similar to your 216. In my various spare-parts motors I have found both converted rod insert shells, and original rods w/direct babbitt.
I recently ran the cost estimates and I could not find the cost of polishing , (or grinding) a crankshaft, and boring new big ends of the piston rods, checking for straightness, ect. anywhere near a cheap $200 for an insert conversion! Shell inserts alone were expensive. Then there is the possibility of needing new pistons and new rings and new ???
As others have said, I would try and keep the direct babbitted rods if they can match your crank dimensions easy by de-shimming. There is no more or less of a babbitt thickness on the shell inserts. De-shimming will cheaply take up some slop in an old engine.
I would recommend first plasti-gauging those rod and crank bearings to give you a better idea of the true conditions of the bearing clearances.
Wishing you best of luck!
