The screeching should have stopped not just got quieter! (I missed that on post#15)
Listen through the top of the cap as suggested above and get somebody to rev it to the "quieter screech" to see if it is coming from the new OPDA or not.
Listen through the top of the cap as suggested above and get somebody to rev it to the "quieter screech" to see if it is coming from the new OPDA or not.