I've always used those calipers and found them OK. They are probably the worst of the lot but still OK if not stuffed. They are popular for Torana owners who want to fit HQ brakes, they use HQ-WB stubs, UC Torana caliper alloy bit (almost the same as yours) and the cast pad carrier off your calipers (bit with HOLDEN on it). The Torana caliper has a top entry hose and a recessed lower attachment bolt to clear the tie rod.