Converting tach mechanical to electric
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
Converting tach mechanical to electric
Whats involved with converting an early C3 (1970) tach to electric. I am assuming I can pick up a 75-77 tach and put my tach face on it.
Has anyone actually done this?
Has anyone actually done this?
Pro
Joined: Mar 2003
Posts: 553
Likes: 1
From: Valparaiso IN
Originally Posted by 70 LS1
Whats involved with converting an early C3 (1970) tach to electric. I am assuming I can pick up a 75-77 tach and put my tach face on it.
Has anyone actually done this?
Has anyone actually done this?
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by mrvette
I used the 75+ tach stock, didn't bother swapping plates, as it was so close anyway, not worth bother....
Pro
Joined: Mar 2003
Posts: 553
Likes: 1
From: Valparaiso IN
QUOTE=jackson]AFAIK ... '71 & earlier have greenish cast to numbers & tickmarks ... '72 up are white (like '75-'77 elec).[/QUOTE]
[IMG]
[/IMG]
The 75 to 77 have a different font style to the numbers too.. Swap the faceplate....
[IMG]
[/IMG]The 75 to 77 have a different font style to the numbers too.. Swap the faceplate....
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Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
Originally Posted by Artsvette73
You will need an Hei distributor, Tach filter, and related wiring
Racer
Joined: Oct 2005
Posts: 251
Likes: 0
From: Grand-Falls New Brunswick
I have a 74 and put 75 tach in it,but didn't swap the face because there was not much difference.A good vette guy will know the difference when you open the hood anyway.The tach filter is seperate from the board,but i was told by a very good corvette guy not to bother with the filter and i didn't put one and it works fine.After the hei is installed,3 wires one to the dist.,one to ground,one to ign.power.
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
Originally Posted by Howy
The tach filter is seperate from the board,but i was told by a very good corvette guy not to bother with the filter and i didn't put one and it works fine.After the hei is installed,3 wires one to the dist.,one to ground,one to ign.power.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by 70 LS1
Whats involved with converting an early C3 (1970) tach to electric. I am assuming I can pick up a 75-77 tach and put my tach face on it.Has anyone actually done this?
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by 70 LS1
What? I don't even have a distributor. My PCM outputs an electric tach signal which is why I am switching to an electric tach.
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
i have not done this yet but i am going to. call clocks by Roger. www.corvetteclocks.com .
you send him your old mech tach and he fits it with a new elec tach, uses the same face and all. even repaints the face to freshen it up.
i am also sending him my spedo to rework. he will reset it to 000000 and repaint and touch it up also.
you send him your old mech tach and he fits it with a new elec tach, uses the same face and all. even repaints the face to freshen it up.
i am also sending him my spedo to rework. he will reset it to 000000 and repaint and touch it up also.
Melting Slicks
Joined: Nov 2003
Posts: 2,668
Likes: 118
From: St. Charles Mo
CI 5 & 8 Veteran
Originally Posted by 70 LS1
Whats involved with converting an early C3 (1970) tach to electric. I am assuming I can pick up a 75-77 tach and put my tach face on it.
Has anyone actually done this?
Has anyone actually done this?
The fastest and easiest way to solve your problem is to put your hands on a working 75-77 tach and send it down to someone like Corvette Intruments in Fla. They will re-screen the faceplate to look just like your 70 green number tach. You can even specify the redline. IMHO it is not worth messing with trying to replace the faceplate with your old one and live with the hole mismatch for $50. Now, if the tach doesn't work, that's a little different. You will be getting into more bucks cause those replacement circuit cards aren't cheap (>$90). Total job to replace electronics and re-screen faceplate is north of $165. This of course doesn't include the cost of the original 75-77 tach.
The lowest cost approach would be to buy a defective 75-77 Tach (pay <$20), fix it by replacing the bad electronic parts and proceed as discribed above.
I had to do it both ways when I repaced the tachs on RamJet and the 69 FI vert.
Bullshark
