1991 gmc topkick 366ci 6.0liter gas. have knock only under load. could it be spark knock?

Question

replaced lifters,rod,main brgs,oil pmp,runs lots better still have knock. snds like rod under load.has over 200,000mi well maint.at start up has knock but dissapp when wrm. wouldnt wrist pin knock const. timing set 6*btdc.

Answer 1

I thought timing was 0 deg.? (disconnected)

You could have a rod bearing spinning around, and occasionally seating properly.

Answer 2

If you have replaced all that and you are sure of the timing, i would thinl wrist pin slap. Does the knock travel with the rpms or quit as rpm increase?