snomobeelr Posted December 14, 2022 Share Posted December 14, 2022 71 Monte . It has the factory wiring and Tach in gauge cluster. I have a Davis DUI distributor and Coil. Do I need any sort of filter for the Stock tack in the Dash? Mine tach went out and Im replacing it. I actually read something for once and it says "you need to buy an adapter to lower the voltage to the GM factory voltage." Has anyone done this ? Dash Tachometer 6500 RPM Fits 1971 Chevelle / Monte Carlo / El Camino This dash tach has the 3 screw design just like the original. This item is sold individually only. Tachometers will work with factory GM points or factory HEI ignition. When using an aftermarket ignition system likes MSD, Accel, Patronix, ect. A lot of these systems generates higher output voltage to the tach lead than what a factory GM tach can handle. Factory GM tachs can operate on voltage ranging from 11.2 to 14.7 Most aftermarket ignition systems generate over 18 volts. You will need to buy from the manufacture of your ignition system an adapter to lower the voltage to the GM factory voltage. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted December 14, 2022 Share Posted December 14, 2022 I have a pertronix ignition system in Barn Find, 71 402. She has factory gauges and the factory tach is working fine with it. Factory wiring, no filter. I can say, if you are using an HEI style distributor make sure you have a 12 volt source powering it. The factory coil/resistance wire does not supply 12 volts when running. 2 Quote Link to comment Share on other sites More sharing options...
DragCat Posted December 14, 2022 Share Posted December 14, 2022 The way I'm reading your directions, and someone correct me if I'm wrong, is you only need to add "parts" if your running "upgraded" ignition like MSD. The PO had a GM HEI on my 70SS454 when I bought it, The coil went bad and I replaced it with maybe a DUI maybe a another brand coil kit. The new crate also has a HEI no issues with the factory tach. My buddy gave me his MSD 6AL when he upgraded to the 7, when I researched doing the upgrade (still pending) there were a few extra parts I had to purchase to make it play well with the HEI. Quote Link to comment Share on other sites More sharing options...
Scott S. Posted December 14, 2022 Share Posted December 14, 2022 With the new tach, you might not notice issues at first without the regulator. Montelishi arrived with a HEI distributor and Accel coil pack. The first couple years were fine, but this summer I've noticed that the tach spikes on start up, and takes a few minutes of running to settle into the proper readings. Just food for thought.... Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted December 15, 2022 Author Share Posted December 15, 2022 Your reading skills are better than mine 😃.. I didn't catch the Upgraded part.. I had the original tach in the gauge cluster worked for a long time with a MSD HEI distributor. Then I went with the DUI distributor and it went out after some time. I actually had the cluster sent out to redline in Tennese. Fixed the tach and the Fuel gauge. The tach worked for a while and then went out again. Redline fixed it it under warranty. It went out again. Ive jus been using an Autometer Tach on the Pillar for the past two seasons. Since she in garage for winter figure Id fix it again. I ordered a new Tach from the Parts Place and saw that disclaimer. I called DUI and they said it should be fine. Im thinking the original Tach is just past its prime. But at the same point. I really don't like dropping the dash and pulling the cluster. Hopefully my last time. But I doubt it .... And now I get to try and reattach the burl wood again too.... Corner poped out a little. 1 Quote Link to comment Share on other sites More sharing options...
DragCat Posted December 15, 2022 Share Posted December 15, 2022 10 hours ago, snomobeelr said: Your reading skills are better than mine 😃.. I didn't catch the Upgraded part.. laughing, if I were doing the project I would have posted the same question, easier to ask than smoke new parts Quote Link to comment Share on other sites More sharing options...
Scott S. Posted December 15, 2022 Share Posted December 15, 2022 After checking the Accel/Holley website, I found the part you're inquiring about..... (SN20). but I assume that every manufacturer has a version to fit their components. Much like how gauge manufacturers use there own sender units and none of them are compatible with each other or factory units. The thing looks like a rubber stopper with 3 wires coming out of it..... Going to give it a try and see if it solves my tach issues. Quote Link to comment Share on other sites More sharing options...
DragCat Posted December 16, 2022 Share Posted December 16, 2022 On 12/14/2022 at 3:55 PM, Scott S. said: Montelishi arrived with a HEI distributor and Accel coil pack. Hey Scott, educate me.I thought the HEI dizzy had the coil in the cap. Or are you running some additional ignition stuff? Quote Link to comment Share on other sites More sharing options...
Dtret Posted December 16, 2022 Share Posted December 16, 2022 1 hour ago, DragCat said: Hey Scott, educate me.I thought the HEI dizzy had the coil in the cap. Or are you running some additional ignition stuff? It could have been an accel coil in the cap. I put one of them in my 77 Monte back in the day. 1 Quote Link to comment Share on other sites More sharing options...
DragCat Posted December 16, 2022 Share Posted December 16, 2022 Ive posted the video I found when researching what's needed for an MSD with an HEI . He shows the extra parts needed 1 Quote Link to comment Share on other sites More sharing options...
Scott S. Posted December 16, 2022 Share Posted December 16, 2022 18 hours ago, DragCat said: Hey Scott, educate me.I thought the HEI dizzy had the coil in the cap. Or are you running some additional ignition stuff? Just the "super coil" that mounts on top of the HEI cap..... I think it's part # 14065, or something like that. This is the best pic I have at the moment. 1 Quote Link to comment Share on other sites More sharing options...
Scott S. Posted January 20, 2023 Share Posted January 20, 2023 Found this on a fellow Classic Chevrolet site. It's for those who are still using the factory original tach with an HEI ignition. Just in case anyone was curious. Quote Link to comment Share on other sites More sharing options...
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