Vega Tachometer - "I killed 2 over 35 years ago"

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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Wed Jan 10, 2018 5:35 pm

I do not know firsthand if the early points ignition Vega tach is any different from the later HEI version. I never owned an early GT. The Cosworth would presumably have HEI, but the calibration would be wrong for your V6.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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1972 Chevrolet Vega Hatchback


Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby 74_Vega_GT » Fri Jan 12, 2018 10:41 am

Thanks again for the input. So, I'll get in touch with Tim McCabe somehow and send off the 8K Cosw. tach. for testing and re-calibration and go forward from there. I did discover that I have 2-120 MPH speedos. One is from a 74 without the blue KMH dial. The numbers and face plate are a little faded but I might just live with it.
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Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby 74_Vega_GT » Mon Jan 15, 2018 10:59 am

Thanks for the info on the MSD adapter, but it creates new questions. The PDF that I read concerning the 8910 and 20 adapter differentiates between the ignition pulse and the ignition voltage. What I need to know is, did all 75 Cosworth Vegas have electronic ignition? Did all Cosworth Vegas come with the electronic fuel injection or were some available NEW with the dual Weber setup and would thaty make a difference as to whether or not it had an H.E.I. system or a points system.?? I am hoping not to kill the Cosworth 8K rpm tach that I have. How does one know when an adapter is needed and which of the adapters is needed in this instance? We are using the inside and outside harness from the 74GT.
Also, the wiring diagrams I downloaded here on the 74 and 75 Vega show no tachometer wiring, Is there a Mitchell wiring diagram for the GT dash that I may have missed?
Thanks in advance.
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Location: Central Florida

Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby spencerforhire » Mon Jan 15, 2018 8:20 pm

I presume all Cosworths had some form of breakerless ignition, so therefore a tach from one should work fine. GM tachs are voltage triggered. The current triggered setup is found on 1960's Fords. If you want some insurance against damaging that rare 8000rpm tach, I suggest the 8920.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2442
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

Re: Vega Tachometer - "I killed 2 over 35 years ago"

Postby dindin » Tue Jan 16, 2018 11:17 am

Cosworth's all use the HEI ignition and they all came with Fuel injection from the factory,

AL
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