I've got 63 C20 myself and will have the same problem you have now. Most of the C20s and above with manual trans, have a drum brake on the back of the trans for the e-brake. When replacing the trans with an auto or ??? you lose the drum brake. The problem isn't the under dash e-brake, that's basically the same from 60(?) to 72, it's the e-brake cables off the rear axle. The Eaton does come with an e-brake setup, it's just hard to find. I had another 63 C20 with an Eaton and a TH400 that had the e-brake lever under the dash. Maybe some one else has a different solution.
Larry
