Factory Tach question

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Factory Tach question

Postby boneheadzz » Sun Aug 13, 2006 2:09 am

Is anyone using their factory tach? My car is s v-8 swap and I was wondering if the factory tach can be converted to use on a v-8 using a MSD 6-AL?
Also, is it accurate compared to say a Sunpro tach or Autometer?
It just seems to be less cluttered to use the original if it's possible...
72 Vega Kammback GT 350/350th 9 inch
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Postby monzaman69 » Sun Aug 13, 2006 2:33 am

I know it can be done (At least on the monza)

My mirage had a 6-AL when I bought it and the factory tach works fine.

Can't tell you much more than that, as the car is 2.5 hrs from me...

I'm sure someone here has wiring info.


1975 Monza 2+2 Basket Case

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Postby cosvega76 » Sun Aug 13, 2006 6:47 am


I pulled a circuit board out of a Camaro tach and put it in my Vega tach. Actually, any V8 tach circuit board from the late '60s through early '70s will work. I've used ones from a '68 Impala and '70 Nova, although few of these cars had factory tachs.

As far as accuracy, they aren't the best. I've checked mine with my MSD tester and the further up the scale, the worse the error is. I have hooked up an MSD RPM Operated Switch through my oil pressure idiot light for a shift light. Rev it 'til the oil light comes on, then shift!!

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Postby doogiediamond » Sun Aug 13, 2006 10:57 am

You will want to contact Tim McCabe in this situation.
He has converted many of our factory tachs to read for V6 and V8 engines.
He converted my 4cyl tach to read for my 231 and has yet to falter
He is a real nice guy to work with and his work is just as nice.
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