I have been getting knock at low boost
15 -18 Lbs. Trans is a 400. After letting out at the track or WOT I get a some what loud moan from some where. this is my first 400, i know there are some big parts in there. May be its normal. I run 85, fuel test at 85 plus, 4.1 stage 2 ,160, duty cycle is around 50% at 18 lbs. All was good then all of the sudden knock started showing up. Feels like something is tight when i get out of it.