I've been wondering if organic would work better than semi-metallic? On the other hand I put on the fresh calipers with the old pads and un-turned rotors and old master cylinder and the truck basically stops the same as it does now with all the new stuff... I've also wondered if the original manual master was different from the two I've had? or try what poorboy suggested with the dimples in the adapter brackets. I've driven it a fair amount around the neighborhood practicing stops but I've yet to really get up to speed. Everything has been clean clean clean.