I did that in my 65 Newport w/ 383 around 1997. Indeed, I did complete re-ring and hone with engine in car. I changed just the rod bearings since the main bearings looked fine. You do have to pull the rear main cap since the oil seal is part of that, as I recall. Mine was a rubber 2-piece seal. The original might have been graphite rope, though I saw no sign the engine had been touched inside. You just push the top half of the rubber seal around to get it out. I cleaned the seal cavity by pulling a cloth w/ gasoline thru it. Put a drop of superglue on the ends to mate the 2 halves, and push around so their parting line is staggered from the bearing block. I recall that you need "anaerobic sealant" on the faces of the bearing block to prevent an oil leak thru the gap. That is a hi-temp superglue I think. Maybe just on the small block I later did. I don't recall jacking the engine up to get the pan off, but fairly simple once you loosen the motor mounts. Once you raise it 1-2", support w/ wood blocks off the K-frame and remove the jack. Be careful not to mess up the oil pan. I usually try 2 jacks w/ rods against the motor mount tabs.
