Parking break

I have a 77 vette. I replaced the shoes, all new hardware as well as new rear cable. I can only get them to work when the car is in neutral. When she is in gear she just keep on going! The adjusters on the shoes are as far as they can go before the rotors lock and all of the slack is taken up on the equalizer connection. any solutions to my problem

The Parking Brake is just that...for PARKING!

Good luck finding one that will actually STOP a rolling car from moving! (They will hold better in reverse than forward, tho.)
If your rotors have had the inside surface for the e-brake machined anytime in their lives, you're not likely to ever get them to stop the car unless it's barely moving. If you park on a slight incline, apply the brake, and the car doesn't roll on down the hill, then the brake is working as intended.
Now then, if you replace the rotors with NEW ones, you might be able to slow the car down effectively with the e-brake, but don't expect it to EVER lock the rear wheels up...it just ain't-a gonna happen.

Thanks again man, you came to the rescue again!

Every year I have to perform a braking test at our DMV (Motor Vehicle Registry MVR here in Oz) and they guys are amazed at the results (no power assist).  Especially when I get to test the rear brakes, that's when I tell them that the rear brakes are identical to the front (smaller pistons though).  But when it comes to the park brake, mine gives a good stopping result.  I've got them adjusted to the point where there is just a slight amount of drag when released.  i.e. you can hear them in contact with the drum part of the rear rotors but no appreciable friction when turning the wheel while up on stands.  I wouldn't like to stop the car with them though.