Team, Why does the factory tach, not seem to be able to keep up with the engine rpm's??.
A lot of LS6 owners are having this anomaly........
The rev limiter is bouncing BEFORE the tach needle get's to the redline???.

Consider the PCM computer only operates at less then 17 Mhz and your P/C is 200 Mhz to 1 Ghz and now you know why.

With that slow of a CPU at higher loads and RPMs the PCM cannot handle all the functions and monitoring thus the RPMS is considered less of a importance and is not updated as quickly as other functions needed for the engine to operate.

If your into shifting close to the limits then install a shift light, use one that uses LEDs since they will light faster then one that uses a bulb and set it to come on a few hundred RPMs lower then rev limiter, thus when it does come on you will be close to the true limiter RPM.

team, thanks.......many a guy has been asking this question, and no one gave or knew the answer score 1 for you!!!!!!