The 'BRAKE' light in the dash of my 1981 Corvette turned on so I added some brake fluid to the master cylinder but the light Still is on. The emergency brake never worked while I've had it but that's not my main concern unless its the cause of my problem.

I believe the fluid/brake light is only intended to indicate the parking brake is on or the master cylinder reservoir is low . ?????

Wrong !!!!!! problem's with ABS can also turn on that light as well ! Take it a have codes checked .

Low fluid level in master cylinder reservoir can also illuminate the cluster brake light. If the level is low, refill and check for leaks.

ok your beemer doest need brake fluid added unless there is a leak in the system. you have brake pad wear indicators that light up dash light when brakes get low. the fluid in system goes down as pads wear fluid does not need added to system. at a glance at master cylinder i can tell if pads need looked at. the master cylinder is under engine cover at fire wall drivers side remove and look but dont add unless a leak is present and then have repaired.

check the brake fluid level, there is a float in the resavor when you stop all the fluid moves to the frount of the resavor causing the float to drop and turn on the light. fill the master cylinder with DOT 3 brake fluid.

Could be this...
Master brake cylinder may be low on fluid. If you have a leak you would also have braking problems. If it is low, it may be due to thin brake pads. The pistons in each brake caliper would be further out, and they take brake fluid out of the master cylinder to do it. So, adding more fluid may turn the light off, however you should have your brake pads inspected. Also, adding more fluid now will make a big mess when the pistons are squeezed back into the calipers to accomodate new brake pads. All that fluid has to go somewhere, and it will run out the top of the master cylinder.

Also, while your checking the fluid level look at the electrical connections on the master cylinder and make sure they are clipped all the way in.

could be a bad brake light switch which is mounted near the brake pedal under the dash try adjusting the plunger which contacts the pedal maybe its on going in far enough otherwise replace the brake light switch

Tr adding brake fluid to the master cylinder fluid cup.

brake system not purged properly, might have air inside or front brakes have leak

No the light and chime does not indicate worn out brake pads or shoes.
However, you were correct to add fluid to the correct level.
Just to be clear, you are talking about the red brake indicator light on the dash and is not accompanied by the amber ABS brake light.
If the ABS light is not involved, there is a magnetic switch located in the brake master cylinder. When the fluid level is low, it triggers a switch in the master cylinder and causes the light to come on.
Some times a "gentle" tap on the master cylinder reservoir will loosen the stuck float and turn the light off. One way to verify the switch is causing the issue, you can disconnect the harness connector at the master cylinder and the light should go out.
Start there and let me know.
Regards,

you will have to remove the master cyl no need to dissconnect the lines and dissconnect the vacuume line and from inside the car under the dash dissconnect the brake pedal from the shaft running to the booster. and remove the 4 mounting bolts that hold the booster to the firewall and pull foward in the engine compartment.
as long as you dont dissconect the brake lines you wont need to bleed the brakes.
good luck
paul