Nope. Those won't work. Pressure plate bolts must have the raised shoulder right under the head in order to center the pressure plate. Without that type bolt, the pressure plate will be off center and cause a vibration. I had no problem with the 1/2" head bolts I linked to above and I used a 10" clutch on Vixen with the scalloped pressure plate and there was plenty of room to get to the bolts. I've not found a 3/8" head anywhere. He could also use allen head bolts, but I've not seen those in a pressure plate bolt either.