Distributors - Tach Drive - universal vs Corvette
Thread Starter
Race Director
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From: North of Toronto - Ontario
Distributors - Tach Drive - universal vs Corvette
So I keep seeing some Distributors listing the tach drive as universal while others say Corvette and I've always wondered if there was actually any difference in them, like the angle of where the drive came out or something. Somehow I don't think there would be any difference but MSD calls it a corvette while DUI says Universal
Just curious if anyone's actually seen a difference or not
M
Just curious if anyone's actually seen a difference or not
M
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
No diff ... MUCH prefer DUI quality, fit, form, function to msd
know nothing bout em but have ya seen these two ?
https://progressionignition.com/shop...ap-distributor
https://progressionignition.com/shop...ei-distributor
know nothing bout em but have ya seen these two ?
https://progressionignition.com/shop...ap-distributor
https://progressionignition.com/shop...ei-distributor
Le Mans Master
Joined: Mar 2001
Posts: 6,240
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From: Watkinsville, GA and Glen Cove, NY
I could be wrong, but I believe the difference with MSD is the the Vette cable is square so you need to use the little adapter. No experience with other cable drive tachometers to confirm this though. This is the piece they say is needed for the Vette tach’s.
https://www.vividracing.com/-p-15164...oaAlSUEALw_wcB
https://www.vividracing.com/-p-15164...oaAlSUEALw_wcB
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I know on the MSD the tach drive is located in a different position. I had to mod the passenger side ignition box shield mount to get the fit where it needed to be to get the timing perfect.
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
M
Thread Starter
Race Director
Joined: Apr 2011
Posts: 11,183
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From: North of Toronto - Ontario
Thought maybe the MSD was a "Corvette" one because it was right, guess not
M
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
.An industryy standard (including GM) for cables' ends is 0.104" square (often round cable core simply compressed into a square cross-section)
OE C3's dist & tach And trans & speedo use 0.104" square drive.
Another standard is tang drive (there are several configurations; typically a round ferrule with one or two tangs protruding 90* from core).
IIRC, Mallory, Stewart Warner, Aircraft and Boats often use tang drives.
https://www.speedwaymotors.com/MSD-8...iABEgL1M_D_BwE
.
OE C3's dist & tach And trans & speedo use 0.104" square drive.
Another standard is tang drive (there are several configurations; typically a round ferrule with one or two tangs protruding 90* from core).
IIRC, Mallory, Stewart Warner, Aircraft and Boats often use tang drives.
https://www.speedwaymotors.com/MSD-8...iABEgL1M_D_BwE
.
Last edited by jackson; Apr 30, 2020 at 10:21 AM.
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Thread Starter
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
.An industryy standard (including GM) for cables' ends is 0.104" square (often round cable core simply compressed into a square cross-section)
OE C3's dist & tach And trans & speedo use 0.104" square drive.
Another standard is tang drive (there are several configurations; typically a round ferrule with one or two tangs protruding 90* from core).
IIRC, Mallory, Stewart Warner, Aircraft and Boats often use tang drives.
https://www.speedwaymotors.com/MSD-8...iABEgL1M_D_BwE
.
OE C3's dist & tach And trans & speedo use 0.104" square drive.
Another standard is tang drive (there are several configurations; typically a round ferrule with one or two tangs protruding 90* from core).
IIRC, Mallory, Stewart Warner, Aircraft and Boats often use tang drives.
https://www.speedwaymotors.com/MSD-8...iABEgL1M_D_BwE
.
M
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
You figure their just calling it a Corvette tach drive because it has the smaller cap? Maybe fits better than an large cap? I don't think it would fit under the shielding though, looks tall, although I do like that style of wire connection over the points style I still think they are a lot taller and wouldn't fit under the sheilds.
M
M
Le Mans Master
Joined: Dec 2006
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Likes: 1,028
You figure their just calling it a Corvette tach drive because it has the smaller cap? Maybe fits better than an large cap? I don't think it would fit under the shielding though, looks tall, although I do like that style of wire connection over the points style I still think they are a lot taller and wouldn't fit under the sheilds.
M
M
The large cap will not. As for semantics, the only other tach drive dizzy I know of is early small T Birds, witch have their own set up.
Perhaps DUI just avoids the use of the word "Vette", which would require GM licensing.
The MSD unit requires their box, the HEI does not. Either way, original appearance is gone.
Last edited by Big2Bird; Apr 30, 2020 at 11:07 AM.
Thread Starter
Race Director
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From: North of Toronto - Ontario
Original appearance has never been one of my strong points.
My points distributor needs rebuilding, the shaft is fairly loose. I stuffed a cheap ebay HEI unit in with all of the important pieces switched to "better" parts so it's really just a housing at this point running with a separate MSD box and depending on what day it is a coil in cap or separate coil.
For no particular reason other than being able to run the shielding again I was looking at options the other day (small cap hei without tach-drive + convert to a newer electronic tach or convert mine to electronic, small cap version with tach drive, find the parts to rebuild my points one) doesn't matter as they all come out pretty close to the same $$$
But anyway, that's when I saw the universal vs Corvette call out again and finally decided to ask
Maybe I'll just ignore it for another season (if we get a season this year...)
M
My points distributor needs rebuilding, the shaft is fairly loose. I stuffed a cheap ebay HEI unit in with all of the important pieces switched to "better" parts so it's really just a housing at this point running with a separate MSD box and depending on what day it is a coil in cap or separate coil.
For no particular reason other than being able to run the shielding again I was looking at options the other day (small cap hei without tach-drive + convert to a newer electronic tach or convert mine to electronic, small cap version with tach drive, find the parts to rebuild my points one) doesn't matter as they all come out pretty close to the same $$$
But anyway, that's when I saw the universal vs Corvette call out again and finally decided to ask
Maybe I'll just ignore it for another season (if we get a season this year...)
M
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,231
Likes: 9,371
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I went with the stock style distributor (before the MSD) and converted it over to a breakerless HEI system, It worked great until the bushing cracked that held the shaft down in the distributor. I had the MSD on the shelf so I tossed it in.
Race Director
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From: Forked River NJ
For all the money being spent on these tach drive distributors just convert your tach to electronic. The cable drives suck anyway. They are bouncy and when running through the gears and if your motor rpms quickly the tach in inaccurate. Go electronic! 
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
adapter is required w/ msd 8572 and it comes with it
https://documents.holley.com/8572.pdf
Last edited by jackson; Apr 30, 2020 at 08:04 PM.
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
Yes I see it now, so the "corvette" distributor needs an "adapter" to work with GM square cables 
I'm not actually looking to change (again) right now, (pus can't warrant spending $700 on a distributor), really just wondering why some called it a universal and others called it Corvette tach drives
M
I'm not actually looking to change (again) right now, (pus can't warrant spending $700 on a distributor), really just wondering why some called it a universal and others called it Corvette tach drives
M