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Quick Specs


Since 1957, AutoMeter has set the standard in performance, accuracy and durability with their legendary Tachometers. The absolute pinnacle of engineering and technology, it’s no wonder AutoMeter can lay claim to more motorsports victories than every other gauge manufacturer combined. The patented air core meter movement, wound in house to exacting standards, can move the needle from 0 – Maximum RPM in 333 milliseconds. An ultra-bright LED shift light guarantees you hit your shifts perfectly, every time. An inaugural inductee to the Hot Rod Speed Parts Hall of Fame, no other tachometer on the market has had anything approaching its impact on professional racing. Built for a lifetime of service under the harshest conditions, this is the no compromise tach for no compromise builds. When you’re ready for the best, there isn’t another choice.
Feature Points
  • Traditional incandescent lighting illuminates around the perimeter of the dial
  • Compatible with most 4, 6, and 8 cylinder engines (2 - 4 pulse per revolution ignition signals) with points, electronic, and most 12V high-performance racing ignitions.
  • 12 and 16 volt compatible, well-suited with nearly every street car or race car electrical system
  • Gauge kit includes bulb and socket assembly, red and green bulb covers, mounting hardware, and detailed instructions for installation
  • AutoMeter’s race proven air-core electric tachometers provide quick and accurate readings with a needle so responsive it can go from 0 - full scale in 333 milliseconds
Ships With
  • Bracket Included
California Residents: Prop 65 WARNING prop65 Cancer, Birth Defects and Reproductive Harm


Rated 3 out of 5 by from Sports Comp Tach not working Purchased this 3 3/8 Sports Comp tach for my classic mustang. I am aware of the quality of Autometer gauges. BUT, the tach did not register needle movement other than a blip when I applied power ON. Switches were set for V8 and the 12v lighting worked. Confirmed my signal wiring working with my original Cobalt tach. This model of Tach has white bulb lighting. I exchanged for a Sports Comp II tach that has LED lighting.
Date published: 2021-06-13
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do I need any kind of wiring harness ?

Asked by: zmarine
The 3991 would not include a harness. We offer a full instrument set harness in 2198 and we also offer 3299 to assist in creating your own harness. You can also just crimp ¼” spade terminals to wires to create your own.
Answered by: Sarah from AutoMeter
Date published: 2023-03-05

Is 3-3/8 the overall diameter including the case? If so, what is the diameter of the face?

Asked by: John Ha
The overall Diameter for this tach is 3 ¾’’ and the actual hole size is 3 3/8’.
Answered by: Sarah from AutoMeter
Date published: 2021-11-11

i have a msd 6240 box with no" grey"wire .where do i pick up signal for tach

Asked by: hubedoobeedoo
Thank you for your question. The signal would be from the distributor since the MSD does not have a tach output on it.
Answered by: Sarah from AutoMeter
Date published: 2021-07-27

I purchased the sport comp instrument cluster for a 1963 GMC. The tach did not come with a light like the other 5 dials did. Why?

Asked by: Al5113
Thank you for your question. The bulb is internal on the unit and there is a dust shield that would need to be removed in order to see it.
Answered by: Natalia from AutoMeter
Date published: 2021-03-11

Is there a electrical plug that fits the back connector of this tach.

Asked by: DanLam
Thank you for your question. Yes, it is P/N: 3299.
Answered by: Natalia from AutoMeter
Date published: 2021-03-11

Does this tach work with this 3-3/8", PEDESTAL W/ CHROME CUP Product #5203

Asked by: 6T5 LeMans
Hello! 3991 will work with 5203.
Answered by: Natalia from AutoMeter
Date published: 2020-12-03

Will this tachometer fit my gen3 hemi MSD6013 system? I was told by MSD that I need a 12v square wave.

Asked by: Truckpuller
This will work with your MSD system.
Answered by: Steve from AutoMeter
Date published: 2020-05-20

Does this tach have the port to plug in the superlite shift light? If not, do you have an in dash tach that does have this feature?

Asked by: Anonymous
Thank you for your inquiry. This tachometer cannot operate a shift light. We make no in-dash tachometers with this feature.
Answered by: Jim from AutoMeter
Date published: 2020-03-13
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