First off im new here so first hi to all you, second i have an 89 camry 2.0 auto, owned it about 4 years now have so much invested its silly to sell but i didnt know it but the cooling system is rusted beyond belief from previous owner i mean i flushed it 4 times and brown goo sits at the bottom of the bucket. I dont really want to buy a new motor unless i have to because this one isnt dead it runs decent but what options do i have about the rust in the block? Its not my daily anymore since it has some issues but i would like to get it back to being efficient and get its power back.

 

i'd just keep flushing it. or run it till it finally dies.

 

Try backflushing it, and the chemicals too. I assume you are removing the plug in the engine block to flush that too.
If it doesnt over heat you ought to be fine, if you find things getting warm maybe change the radiator or have it cleaned out really well.