I have a 1969 390HP 427. I think I have the original timing cover since all of the other parts on the engine are original. My balancer is 7" which is correct for the judging manual but my timing tab is rectangular and does not have a triangular end. The judging manual says that my timing tab should have a triangular end. I have seen that type of tab on the 8" balancer timing covers but I only see the rectangular tab on the 7" balancers like mine. Is the judging manual wrong, or should I have a 7" balancer triangular timing tab?