There should be a knob somewhere ( not sure on the 69 dash?) that you can adjust too what speed you want the needle set at, when you hit that speed where the needle is set or go over it a buzzer goes off. The buzzer is the little box at the very top of the dash assembly.

From what I've seen on other 69/70 Impala speedo's, there was a knob on the bottom of the instrument surround that went up to the back of the speedo.  I think it was a cable joining the knob and the speedo (I think I have a rear view photo of this somewhere, let me check).  Turning the knob adjusted the yellow colored pointer.  Does it look like there is somewhere a cable would go into the speedo?

As 2qwik2c indicates, when your speed matches the speed of the pointer, the buzzer sounds and may scare the crap out of you. 

-- Edited by seventy2plus2 on Sunday 19th of April 2009 05:41:03 PM

Steve,

Was the rear valance panel on the Caprice any good?

Thanks Steve.