My 91 GTA has a low in knock, gets really bad had higher rpms. I was told it sounded like a spun rod bearing so I'm gearing up to rebuild it. Any suggestions on a better cam or other things I should consider when rebuilding this motor. Thanks,

My best suggestion would be to buy an old 350 and rebuild it. You should be able to get a 350 for $500 or less. It will cost the same or a bit less to rebuild the 350 as the 305. The 350 will net you much more HP and torque. You can swap all of the TPI stuff from the 305 to the 350 and you'd only need to get a Calpack (PROM chip and other things ) and a set of 22-24 LB injectors.
Now, don't go too hog wild in the rebuild since you have a 91 it is a speed density system and doesn't like changes without a reprogram of the PROM.