Hmm A red line on a tach never prevented me from over revving. When the valve springs float out, now thats different. The FJ 1100 and 1200 had kind of the same thing going on. The 100 rev limiter would hit like 10,000 the 1200 motor was 10,500 or 11K Atleast thats what we found with the legend cars that run that motor.