I got my "83" chevy silverado running after 5 yrs. sitting it has a 2 to 1 exhaust system, like to put a dual system, do i still need to keep my cat. convertor.

Only issue you would ever face would be "The Man" at the emissions control test building when it's time to go there. Just get a pair of short cats from a junk yard or a friend and put them on your duals. Done, legal, no problem. That 5 liter/305 won't run well without the cats anyway, unless you do a few other things with said removal.

go for deep and loud and the road department will love you for the extra revenue you will be providing with the fines
next the fuel companies will be loving you as well because deep and loud is poor performance and that means extra profits for them
you are replacing an exhaust system but leaving the stock headers on and not putting extractors on
what you need to do is go up 1/2" in pipe size, refit cat converters ( gets you past the smog tests), remove any unnecessary bends and fit the correct muffler
best if you rethink what you want and talk with an exhaust shop specialist as to what you need to get performance , pass the regulations , get economy and still come up with a lower frequency noise
one thing that you haven't considered is this fact ---
deep and loud contribute to driver drowsiness on trips and that makes you loose awareness and fall asleep at the wheel

This code means that the catalytic converter on the passenger side of the truck is not working as well as it should. You probably need to have a new cat put in but be aware that if the engine is running poorly, this code can set because the cat gets overloaded. Often times people replace the cat because of this code, only to have the problem return because they did not fix the root cause of the cat failing. A tune-up will not necessarily solve the problem either. If the engine has a lot of internal wear and is burning oil, the new cat will fail prematurely because of too much fuel and oil coming out of the engine, through the exhaust system.

run a quality injector through the system as the injectors may not be operating properly

Because of the misfire your catlic converter might have been damaged, that is why after the vehicle warms up the cat get colgged and exhaust cannot leave the system.

the o2 sensor is going to be in the exhaust pipe near the cat.or in the exhaust manifold itself on the right side.

There will be one located before your catalytic converter and one after your catalytic converter for each exhaust system you have.
In some cars, there can be 2 O2 sensors before the catalytic converter even if there's only one exhaust system.

Bank 1 will refer to the sensor that's on the same side as cylinder 1 and Bank 2 will mean the opposite side.

Sensor 1 will refer to the sensor before the catalytic converter and Sensor 2 will mean the one after the cat

Backpressure is the result of any obstruction in exhaust flow. Both the converter and muffler create a certain amount of backpressure by design. If the cat becomes plugged, exhaust cannot properly escape and can cause an extreme lack of power. (Engine can't draw in what it can't expell out the other end) Usually the rotten egg smell is also accompanied by a "wheezing" sound in the cat as well.

The engine is running rich, find what is causing the rich run and that will fix the rotten egg smell

It’s your solenoid that is getting hot and the engagement washer inside is what is sticking. There is some heat shield material you can get from the auto parts store to shield you solenoid.