Who's there?

My least favorite type of joke.
In all seriousness, here's the rundown - brand new M50B30 single VANOS frankenstein motor. CP Carrillo piston, K1 rods, VAC coated rod and main bearings, cutting ring HG, chinese GTX3576R. Dyno'd 487 whp, 495 wtq @ 25psi after being tuned Thursday. Friday, took it to it's first drift event - runs great without a hiccup, other than the oil pressure sensor (aftermarket gauge, teed off stock oil pressure switch w/ oil distro block) signal shorting and getting stuck at 5v which in my case read 112.5psi. 20 minutes after leaving the event it develops a loud knocking noise from the engine. I cut the power and towed it home. This morning I started it up to align it on my lift and listen to the exact sound its making. I noticed that the knocking seems to be nonexistent when starting the car, and it seems to be intermittent when free revving the engine. Revved it from idle to 3k, and the knocking noise seems to come and go every couple seconds. My guess is rod bearings, and I'm prepared to tear the engine apart to replace the rods, and grind down the crank and install undersized bearings if the damage to the crank is bad enough.

Just wondering if anyone else has any other ideas? The only thing that throws me off is the intermittent knocking.