74 k10 going 55 mph is at 3,500 rpm

[gmbellew]

also verify speedo is correct with your phone GPS

 

[granthendrickson]

My question is why do you think you have 3.73 gears? it Sounds more like 4.56s or your only getting first and 2nd gear.

I’m not 100% sure but that’s what the build sheet says and it looks stock. Last night I was driving and it did go into third gear.

 

[granthendrickson]

also verify speedo is correct with your phone GPS

Whenever I go through town and drive by a speed check thing it looks accurate. But I will try the phone one

 

[Bextreme04]

How do you know what your RPM is? Factory tach? Aftermarket one? Where are you at in Oregon?

 

[granthendrickson]

How do you know what your RPM is? Factory tach? Aftermarket one? Where are you at in Oregon?

It’s an aftermarket tach, I’m in McMinnville oregon

 

[gmbellew]

It’s an aftermarket tach, I’m in McMinnville oregon

good question about the tach. I am not that familiar with aftermarket tachometers or if there are different types, etc.. but at 3500 rpm the engine should definitely be making some noise. that can be used as a quick reality check on the tach readout. is the engine really screaming at 55mph?

 

[granthendrickson]

How do you know what your RPM is? Factory tach? Aftermarket one? Where are you at in Oregon?

The tach is up by around 220 rpm according to my timing light

 

[granthendrickson]

good question about the tach. I am not that familiar with aftermarket tachometers or if there are different types, etc.. but at 3500 rpm the engine should definitely be making some noise. that can be used as a quick reality check on the tach readout. is the engine really screaming at 55mph?

She’s not quite screaming but she’s definitely up there in the rpm according to my ears lol

 

[granthendrickson]

She’s not quite screaming but she’s definitely up there in the rpm according to my ears lol

Okay I just drove it on a backroad, she is shifting into third gear. The tach was saying 3,400 rpm at 55 however it is up by around 220 rpm. The speedometer is pretty spot on. So given that info the rpm’s at 55 are close to 3,180.

 

[TotalyHucked]

I'm gonna venture to guess either you have way more gear than 3.73 (either the original axle has been regeared or it's been swapped with another axle) or your tach is off more than 220rpms. How did you verify it was off by 220?

 

[granthendrickson]

I'm gonna venture to guess either you have way more gear than 3.73 (either the original axle has been regeared or it's been swapped with another axle) or your tach is off more than 220rpms. How did you verify it was off by 220?

By a timing light

 

[granthendrickson]

By a timing light

The timing light has a tach on it

 

[Old Guy Bill]

I remember some aftermarket tachs having a small 4-6-8 switch for the number of cylinders on the engine….

 

[granthendrickson]

According to this the axle is a 3.73 gear stock axle, how do I go about figuring out wether someone changed the gear ratio?

 

[granthendrickson]

I remember some aftermarket tachs having a small 4-6-8 switch for the number of cylinders on the engine….

Oddly enough this tach (which I bought on Amazon) advertises it works on 4-6-8 cylinders engines however it doesn’t have any switch to change between them