[mgarblik]

Looks like that area between the timing case and the aftermarket balancer needs a little attention. Once the real problem is discovered and corrected, I would carefully trim the timing cover a little and/or the the oil pan lip just to make sure you have .060"+ clearance at the tightest pinch point. Of course verify the thrust bearing and crankshaft end play are OK, which I imagine they are. These are all typical fit issues we have to deal with on every build nowdays. None of the aftermarket parts really "fit" like the factory stuff. From what I understand the only factory part in this entire front assembly is the crankshaft. The crankshaft timing gear can have slight tolerance issues, the balancer, the timing cover and the oil pan. If each of these parts was off just .010" of an inch, you have contact when it's all put together. A scraping, sheet metal sound, possibly. A knocking sound, I don't think so. However, 1300+ posts have been wrong so far, including at least 10 by me. 45 years of building Pontiac V-8 engines, this is in the top 10 of weird ones.