are the brake lines switched?--on a mopar the rear line goes to the front and the front line goes to the rear---each line has its own residual----dont know how the chevy stuff hooks up----the front needs only 2 lb residual (column pressure is enough if mounted on the firewall)---the rear uses about 6-8 pounds of residual-----if you somehow had the rear residual going to the front you would get very significant drag....bob