High rpm in 164

[VLADDS@domain.elided]

Today I decided I was all set for testing the upper end of the rpm range in my
164.
I drove a bit till got to normal temperature then, proceeded to go to
limitator in 2nd gear. To my BIG surprise it went trough the yellow
zone,..trough the 6k and stopped at 6900 rpm, way into the red zone making an
awesome, F1 like sound (well, close enough to that, to my ears..).I then
proceeded to cruise in 3rd gear at around 5k rpm for around 10 mins.
The noise it makes in that range and the immediate throttle response were
.......GOOD.
No special exhaust needed.
However, afther that I made 6 consecutive attempts at the rpm barrier and got
turned down each time at exactly 5900.
What could this difference mean? Is it possible that there are 2 programed
limits and the first one failed?
I don't know the previous owner, but a lot of little signs tell me that this
car was not brought up there in the high range too many times, maybe never to
the limit.
At 6900 the engine had a more vibration-free, balanced run than at 5900.

Vlad 
'91 164L
Long Island

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