JEFF, I REBUILT MY 38 MODEL 41 AND USED 1949 BUICK CONNECTING RODS WITH NEW .O2O OVER PISTONS. I BOUGHT THE PISTONS FROM TERRILL MACHINE SHOP IN TEXAS.I HAD THE BLOCK AND CRANK SHAFT MACHINED BY GOOD MACHINE SHOP.I HAVE ABOUT 3000 MILES ON THE ENGINE SINCE THE REBUILD RUNS GREAT WITH THE INSERT BEARINGS.DONT THINK YOUR MAKING A MISTAKE WTTH THE INSERT BEARINGS.