brake proportioning valves questions

Thanks for clearing that up. Plan sounds good. I've done several BBP disk brake conversions. You'll enjoy the extra stopping power and the security of having steady brakes on those rare days when it rains in west Texas (not West, Texas).

To answer your original question, the Cordoba valve ought to work. The balance may not be quite right, but it was a compromise at best anyway. There is a big weight difference between a Cordoba and a '67 Cuda. The weight balance F/R as a % ought be close. I think I'd be comfortable with it.

The design is to get the fronts to lock up first. When the rears lock first, the tail wags the dog. Don't believe it, watch NASCAR on a road course. When a guy dials up to much rear brake, the rear starts hopping and the car goes towards the weeds tail first.