A buddy just had his engine rebuilt by a reputable engine builder. It's a 327 sbc, new cam, align bored, new bearings etc. The noise sounds like it is coming from behind the thermostat housing. He pulled the intake off and replaced the front 4 lifters and the noise persists. The knock starts at about 2000 rpm. He pulled one plug at a time and the knock is still there. Any thoughts???:CRY:
