MSD distributor vacuum advance question (pics)
Thread Starter
Burning Brakes
Joined: Jun 2003
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From: San Antonio TX
MSD distributor vacuum advance question (pics)
I’ve tried to register twice now on the MSD Forum, but I’m still waiting for my account to be approved. So I figured that I’d try all the experts here.
So I have this brand new MSD distributor, part number 8571, but it doesn’t have the vacuum advance.
Does anyone know if there is a kit or a part number to add the vacuum advance to this distributor?
Or am I SOL?
Also a buddy here at work said that there were issues with this distributor working with a stock Corvette Tach, but he couldn’t remember why. Anyone hear about that?
Thanks
KO
So I have this brand new MSD distributor, part number 8571, but it doesn’t have the vacuum advance.
Does anyone know if there is a kit or a part number to add the vacuum advance to this distributor?
Or am I SOL?
Also a buddy here at work said that there were issues with this distributor working with a stock Corvette Tach, but he couldn’t remember why. Anyone hear about that?
Thanks
KO
Race Director
Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Wow MSD doesn't even offer the 8571 anymore 
There is a Corvette specific one that has the tach drive and vacuum can, 8572
I wouldn't bother with the vacuum advance on a performance engine and the engineers at GM seem to agree with me
This is from their instructions for a new GM ZZ4 engine
"Set spark timing at 32º before top dead center (BTDC) at 4000 RPM with the vacuum advance line to the distributor
disconnected and plugged. This setting will produce 32º of total advance at wide open throttle (WOT). The HEI
vacuum advance canister should remain disconnected. This engine is designed to operate using only the internal
centrifugal advance to achieve the correct timing curve."
There is a Corvette specific one that has the tach drive and vacuum can, 8572
I wouldn't bother with the vacuum advance on a performance engine and the engineers at GM seem to agree with me
This is from their instructions for a new GM ZZ4 engine
"Set spark timing at 32º before top dead center (BTDC) at 4000 RPM with the vacuum advance line to the distributor
disconnected and plugged. This setting will produce 32º of total advance at wide open throttle (WOT). The HEI
vacuum advance canister should remain disconnected. This engine is designed to operate using only the internal
centrifugal advance to achieve the correct timing curve."
Last edited by MotorHead; Sep 11, 2008 at 01:50 PM.
Melting Slicks
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St. Jude Donor '08
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From: Taylor Michigan
Burning Brakes
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Vacuum advance regulates economy during loaded/unloaded conditions.
If all you want is performance, mech advance is sufficient. For a street car, I can't see not using one, considering fuel at $4 a gallon, and only 40 HP or so to cruise at 60MPH.
If all you want is performance, mech advance is sufficient. For a street car, I can't see not using one, considering fuel at $4 a gallon, and only 40 HP or so to cruise at 60MPH.
Burning Brakes
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Race Director
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From: Taylor Michigan
After the 63 models it wasn`t untill ihe introduction of the L88`s that GM went back to no vacuum advance. However most street engines also run with the vacuum hooked up for reasons stated in other replys. I run my engines both ways and those with the higher horsepower without one.
Look close at the distributors in the pictures. The first in the 68 Camaro is a over the counter crate 454 LS7. The second also a new crate engine is a 1965 A990 Race Hemi. in my 70 Cuda. Both cars are street driven at times with 'zero' issues. In fact are a blast...
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Drifting
Joined: Feb 2005
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From: Los Gatos CA
Street driven cars will almost all perform better with vacuum advance. Engines that operate only at high rpm (race engines) have no vacuum, so they don't need vacuum advance. In CA with our crappy gas and warm weather, I like 34* centrifugal in by 2800 rpm and no more than 10* vacuum (full manifold vacuum rather than ported). Just my 2 cents...
Team Owner
Joined: Jun 2001
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From: Virginia USA
There should be a small adaptor that fits inside the hole where the tach drive cable goes into. At least thats the way my 8572 is. Check you MSD kit. The tach drive in your picture looks like it's not installed. The adaptor makes the hole accept the square end of the tach cable.
Thread Starter
Burning Brakes
Joined: Jun 2003
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From: San Antonio TX
There should be a small adaptor that fits inside the hole where the tach drive cable goes into. At least thats the way my 8572 is. Check you MSD kit. The tach drive in your picture looks like it's not installed. The adaptor makes the hole accept the square end of the tach cable.
So I am unable to find this anywhere.
Anyone have an extra one?
Drifting
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From: MS
Team Owner
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From: Virginia USA
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Burning Brakes
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From: San Antonio TX
