I finally conquered the rattling sound that has plagued my 1938 216 for over three years. I have had a fairly loud rattle that comes alive at say 30 mph and above. It used to quiet down some when the engine got warm in the summer. Two years ago I overhauled the motor because of a scored cylinder that existed from the time I purchased it in 2015. I bored it, installed new pistons and rods. I thought by the look of one of the rods that it may have had a little twist to it. When all was assembled, the rattle was still there. Last year I installed all nos rockers and examined all the lifters. The noise persisted. This spring I went to do another valve adjustment and discovered that #5 intake had over .020 clearance. I adjusted it and the rattle almost disappeared. So I examined the pushrod itself. The top socket that the rocker ball fits into had worn down and receded, to the extent that the rod was actually captive on the rocker ball! In addition it was worn so deeply that the range of motion was limited. I replaced the pushrod along with several others and the noise is finally gone!
