Completed the Disc Brake conversion on my 71. I didn't replace the proportioning/metering valve. The rear brakes seem to work but this car has not seen the road yet. Will I have a problem with these brakes? Should I replace the valve with an adjustable one? Thanks

Rear drum brakes use a residual pressure valve to help energize the shoes. The pressure valve can be in the master cylinder or the combo valve depending on the year. With disc this residual pressure will cause the pads to drag.

Probably the best way to find out is to test the brakes on an empty road. Do an aggressive stop from 40mph or more and see if the rears lock way before the fronts. The combo valve is supposed to reduce pressure to the rears to reduce premature rear wheel lock up.

Thanks for your replies. I can't wait for Spring!