Most people don't bother to shim the 54-55 1st series 235. And those that do fall into two different camps. One camp uses plastigage to check the bearing clearance, the other camp (which includes Proffit) believes in miking both the crank and the bearing. It all depends on what you expect from your engine. The real perfectionist will insist on line boring the mains, which requires a special tool due to the different sizes of bearings. Do the bearings have to be exactly round? Not really, but it's your engine and you know what you expect out of it.
