RPM WAY too high at 40MPH

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sharpie

workin' stiff
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Not sure what's going on. My car was an original slant six car, and I got it all-original. Needless to say, the slant is gone, but the 7.25 remains. I believe it's a 2.76-geared rear end. So if that's true, why the heck am I doing 3500RPM at 40MPH?! Note that my foot is barely on the accelerator pedal at this time. It's doing 3500RPM in the idle circuit.

Could this be a kickdown issue (throttle pressure?) or do I maybe not have the rear-end I thought?
 
That is strange. Are you sure your tac is working properly?
 
The tach seems to be working fine. It does have different cylinder settings, so I can try that first I think. It's a cheap tach, but seems to be pretty responsive.
 
Do you feel it shift through the gears sharpie? If not try adjusting the throttle pressure I mentioned in the other post.
 
sharpie said:
Not sure what's going on. My car was an original slant six car, and I got it all-original. Needless to say, the slant is gone, but the 7.25 remains. I believe it's a 2.76-geared rear end. So if that's true, why the heck am I doing 3500RPM at 40MPH?! Note that my foot is barely on the accelerator pedal at this time. It's doing 3500RPM in the idle circuit.

Could this be a kickdown issue (throttle pressure?) or do I maybe not have the rear-end I thought?
Click to expand...

3500rpm with 2.76 gears sounds about right for first gear in a 904. is it shifting?

jack up the rear end of the car, and find out how many turns of the drive shaft = 1 turn of the wheels. (multiply times 2 if no suregrip) to find out how what kind of gears you've got..
 
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