I have a knock in a 3.5 DOHC. I was hoping it was a VLA but in truth I thought it was just a little bit louder. I have done the VLAs, the revving procedure, etc etc... The head looked good but I didn't take the cams out when I did the VLAs, just compressed the valves and snuck the rockers out. Same nasty knocking. Has anyone had something similar? Colapsed piston? I'm in a little to deep here and could really use some advice. I'm terrified that if I take it all the way down to the block I won't really see what's wrong. Help!?

Have you checked the changeover butterflies in the intake for one with a lost plate or screw?

The best way to diagnose noises is with a mech stethoscope, to help localize the noise. It is very easy to distinguish between a noise in the head and one in the block this way, harder to tell if the noise is main or rod bearings, fairly easy to see it it's a slapping piston from a collapsed skirt. Also easy to see if it's a bad idle bearing.

If it's a main or rod bearing, you should see a marked drip in oil pressure, and with a mech oil gauge with the restrictor removed, you can see a marked flutter in the gauge as the oil hole on the crank is covered more tightly.

Thanks a lot Edddy. All of this can help. I did notice that the oil pressure is now lower than it was (was running "high" on the guage) but I did replace the oil block seal, the old one was held together with RTV and one of the ports had been partially blocked, could have put extra back pressure against the sensor... My Ol' Man is comming this weekend, I hope he remembered to bring his stethescope. Hmmm, any thoughts on parts? I keep seeing the cheap stuff on e-bay and wonder if it's the same or at least equal to what Rock and Korum have...