The small sheet metal nuts were called "Palnuts". They didn't really accomplish anything, and I would find most, if not all of them buried in the sludge at the bottom of the oil pan on a lot of stovebolt engines. A properly-torqued rod nut stays in place three days past forever, and one that's not torqued properly doesn't, no matter what sort of locking device is used. 45 ft/lbs. of torque is exactly right for a 3/8-24 rod bolt, with either locknuts or regular ones. What oil clearance did the bearings have when you assembled the rods?
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!