Recently bought and installed a late model, low mileage 440 from a motor home. After running it a few days, I started hearing a very slight rattle on start up. As soon as it gets oil, it seems to go away, however, I now think I'm hearing an ever so slight noise at idle. It bothered me enough that I dropped the pan to have a look. The bearings look great. They are standard size, the rod journals are perfect. .0025 oil clearance. I can grab the rods and when I try to move them up and down on the crank, there is no movement, however, when I try to move the rods back and forth, perpendicular to the crank, there is a lot of movement. You can hear an audible clunk. I'm thinking this is where the noise may be coming from. Time to have the big ends resized?