I recently moved from one state to another and I had some engine work done to my 72 Nova.  My car wouldn't start  I found out why the builder put on a brass distrbutor gear and it ground down some of the teeth on the gear.  I replaced it with an Iron gear... My question is do I need to break down my 350 to see if the brass messed up any other parts. like my cam and pistons?  Let me add I am a very novice engine builder... How bad is this?  All help will be greatly appreciated.  

Your problem is, all those brass shavings ended up going into the oil, and probably the motor.

You need to drop the oil pan, see what's in the bottom. Check the oil pump pickup screen for debris. Change the oil filter to a really good filter, like a NAPA gold, or an AmsOil one. Third, I'd put an oil filter magnet on the motor for a while to make sure you can trap as much as you can. Full oil change. Pull the valve covers, see if there are any metal shavings on the tops of the heads where oil collects.

You might get lucky and the filter and oil pump screen kept most of the shavings from getting into the motor.  

Thanks I just pulled the valve covers off and I didnt see any metal shavings.... I will take your advice do the full oil change and add the magnets. Thanks  

A magnet in the oil system is good insurance, however, solid brass, as used in distributor gears (as opposed to brass plated) is non-magnetic. Therefor, the magnet will not grab your brass garbage.