I am assuming the crate engine was new when you bought it, so that rules out any rebuild problem. There have been some reported problems with excessive cylinder wall clearances on certain early GM Performance Parts crate engines. Since yours was purchased in 00, it may be one of the affected ones, Whether or not you can get the dealer you purchased it from to admit it, that is another story. Your description of the noise sounds like a piston slap due to excessive clearance IMO.
Last edited by 302/Z28; 09-19-2003 at 10:25 AM.