im rebuilding my super c and took the head in to the machine shop to have it rebuilt. i bought the complete rebuild kit off this web site and took the parts in to him. stoped in to see it yesterday and he told me i had a problem with the springs. the old springs have eleven coils and the new springs have thirteen coils . when he puts the keeper inside the spring on the valve and compresses it the keeper catches on the spring. so he tested all the old springs and put them back in, he said he had to shim them. has anyone else ran into this problem? are the parts off this web site quality? thanks