brentlysubaru

I bought a 98 legacy outback with the 2.5 dohc for parts for my 93 impreza. The guy I got it off of just replaced both head gaskets timing belt idlers water pump balancer and oil pump right before he discovered that the right rear strut housing was gone. The engine is fairly quiet at with just a little tick at idle nothing to worry about typical noises but around 2000 or so rpm it almost sounds like a rod knock. You can't hear it sitting in the car but under the hood you can. Is this a normal noise for the 2.5? I was just wondering before I try and swap it into the impreza. Thanks in advance.