1972 BBB. Motor has been together for 5 yrs. 2 months ago while driving it developed a miss, I could hear a lifter clacking. This started happening like clockwork when it got up to temp. When it cools down it would be ok and not miss. I could figure it was Cyl 6 or 8. So I replaced all the lifters on the right side. It was good, drove around town a lot, 300 highway miles, 5 quarter mile passes. Then 10 minutes from home last night it stated missing again, same loud lifter noise. When I originally got this motor in parts, one of the lifters would not fit in the bore, I brought the block to the guys I bought it from and he honed the bore and the lifter moved smoothly. That was 10 years ago, motor rebuilt again 5 yrs ago Cheers!