The one I have is a disc/disc combination vavle. The only factor I can think of is that most older 1tons ive seen with a disc rear were associated with a dually axle, maybe that's whats causing the rear to lock up? . Between 35-45 mph It'll track fairly straight when coming to a hard stop, so its very minute. Ill try a proportion vavle and see if it helps


1950 Chevy 3800
4-53T Detroit Diesel conversion
In the Stovebolt Gallery
More pictures in Photobucket