1997 Dodge Neon Knocking Noise

Recently replaced exhaust manifold, and did some minor repair to the wiring harness and exhaust pipe. I went on a short drive to go do a drive cycle, so I can get the car smogged, when I started to hear a really loud knocking sound from the engine. The sound gets louder and faster the higher the RPM's rev. When the car goes to 50-60 (I had to return on the freeway from whence I came) the knocking sound cuts on and off, a few knocks here, no knocking there. Between 0-40 mph the sound in constant and loud. I read that it was prolly a thrown rod or blown bearing. I tried removing the spark plugs on each cylinder to see if there was any change in the sound and there was not.