[niterydr]

Double check that ignition setup, check the plugs, it looks like 1 cylinder is having it taken to them. Either it is noise from mechanical or detonation..but you'll have be very careful with this one.

Some forged engines are loud. Is the knock sensor new? Torqued down to spec?
Any other problems with the car at all?
Have you tried leaded gasoline with an 11.5-12.0 afr? Something like Sunoco 110 or similar? That should light off relatively easily and is very stable, should let you know if you have a hot spot in a cylinder, a plug that hates you, a weak cylinder, or noise.