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Old 11-19-2006, 02:23 AM
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Vaccuum Advance

I've got a hood on my track roadster now which interferes with my distributor (Davis HEI on a 302 Ford). So now I'm shopping for a shorter distributor. The Mallory Unilite with their "crab cap" will give me lots of room. They're inexpensive and plentiful on ebay but not many with vaccuum advance.
I can remember being convinced by something I read that vaccuum advance provided benefits that I didn't want to be without.
1) Does any one know what those benefits are?
2) Can I assume if a Unilite has a vaccuum advance that it also has a mechanical advance?
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Old 11-19-2006, 05:25 AM
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moving to engine forum........
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Old 11-19-2006, 05:48 AM
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I personally would not be without vacuum advance.
Read this and this
Racers use distributors without advance, street cars canīt really do without it.
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Old 11-19-2006, 05:52 AM
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Quote:
Originally Posted by malc
I personally would not be without vacuum advance.
Read this and this
Racers use distributors without advance, street cars canīt really do without it.
I agree totally...............To bad some of these people that "THINK" they drive race cars dont feel that way.
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Old 11-19-2006, 06:29 AM
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Vaccuum Advance

Vaccuum advance is not necessarily required for a well tuned performance engine in a street car.I unhooked mine almost 3 years ago and I have been very happy with the way my car performs.There was no difference in gas mileage or spark plug life.There is no pinging or detonation or stumble at part throttle from too much advance being brought in via the vaccuum.Although I have a high compression,big cammed,LS-6 Big Block Chevy, and vaccuum advance didnt work very good in my situation,and I tried the Crane advance kit,different springs,different weights,it just plain works better with no vaccuum advance.I'm not saying this is the answer for every application,but it never hurts to live outside the envelope a little bit.Try it and see.You've got a light car,you might be OK with the Mallory distributor you are looking at,it never hurts to experiment.
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Old 11-21-2006, 02:45 PM
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Have you considered a stock points type dist with a pertronix conversion?
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Old 11-21-2006, 04:10 PM
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I personally dont know anyone with that mallory unilite distributor, but i wanted one and went to the local speedshop and they strongly advised me not to use it. He said he has sold 9 of them last summer and only one person hasnt had problems with it. The other 8 have had to buy a replacement optics within a couple months. Like I said though I dont know these people I just thought I would pass along that info and put that out there. If anyone has one here on this forum I would like to know about how its been for you and how long youve had it. I still may want to try one. I just dont want the 90$ a month for new optics.
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Old 11-22-2006, 11:51 AM
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re: Vaccuum Advance

I certainly appreciate the different views and information you guys have provided. It just goes to show that a lot of hotrodding is still "art". I did purchase a Mallory Unilite equipped with a vaccuum advance (I heard/hope they have solved the early failure problem). My car is a light track T roadster under 1800 lbs. with a carbureted SBF. When I went to Schneider for the roller cam I told him I really didn't care about how much power it made but I wanted it to sound like the old "Oscar's Drive-In cams" with lots of overlap. He made me promise not to put an automatic transmission behind it ! I think that having the vaccuum provide the idle advance means I won't have to preload the initial advance an extra 10 degrees to make it idle and take away some flexibility concerning the total advance. Thanks all for the resources and conversation with like minded motor heads.
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Old 11-22-2006, 08:00 PM
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I'm not even going to bother getting into the whole vacuum debate but I will say I've been running a Unilite distributor for a few years now with no issues at all. The Mallory rep suggested I use their coil (needed one anyway) and to install a Power Filter which acts as a voltage spike suppressor so the module doesn't fail prematurely from spikes in the electrical system. The filter plugs right into the distributors harness connector. You can see it between the coil and the distributor. So far so good.

Power Filter
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Old 11-23-2006, 03:16 PM
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I also run the Mallory Unilite with no troubles.The power filter is a must have if you want it to last.
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Old 11-23-2006, 04:20 PM
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Quote:
Originally Posted by DOUBLEDICK
I also run the Mallory Unilite with no troubles.The power filter is a must have if you want it to last.
Love that intake manifold dude!
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Old 11-23-2006, 04:35 PM
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I am doing my 58 Apache in the 70's style.My first truck was a 59 so I am doing to this truck all the things I always wanted to do to my first truck.That is the old Edelbrock Tarantula single plane manifold from the 70"s on a balanced and blue printed 427 with the old cast iron rectangle port heads.In the lounge I started a thread "55 to 59 Chevy truck owners".I have a bunch of pictures posted there.There are some truck posted that are just over the top.Check it out
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Old 11-23-2006, 04:41 PM
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Quote:
In the lounge I started a thread "55 to 59 Chevy truck owners".I have a bunch of pictures posted there.There are some truck posted that are just over the top.Check it out
Just did. Nice truck. You must love rollin' around in her.
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Old 11-23-2006, 04:50 PM
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Yes I do it is a blast.If you go to "classicsandrods.com" you can check out photos of the shows the club has gone to.I took the 58 to the super run .I won a trophy in roaring engines(128 decibels) and 3rd in the slow drags.I didn't win anything in the burn out contest but I had a blast burning up an old set of 31x10.5 truck tires.It is a small club but they are a good bunch of guys.
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Old 11-23-2006, 04:56 PM
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We better take this conversation to the lounge.Post in the 55 to 59 chevy truck owners thread I will catch you there
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