Knocking, engine noise?

I have an 84 camaro that has a 69 vette 350 with a mild performance cam weiand stealth manifold with a holley 650 double pumper, mated to a 700r4 my problem is that I am hearing a knock similar to a lifter/rod knock between 1500 and 2500 rpms. With a stethoscope the sound is heard loudest around starter and bell housing. Any ideas?