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Discussion Starter #1
Hi

I have been on the MSD forum and they have recommended one of two Distributors to suit my 347 stroker build. The 8579 and 8598. Neither of these seem to have vacuum advance and I was wondering what you guys thought about this? Do I need vacuum advance on a fast street car? It seems from what I read that pure mechanical advance is only for race cars but I'm no expert on the matter!!!

Thanks

Martin
 

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Hi

I have been on the MSD forum and they have recommended one of two Distributors to suit my 347 stroker build. The 8579 and 8598. Neither of these seem to have vacuum advance and I was wondering what you guys thought about this? Do I need vacuum advance on a fast street car? It seems from what I read that pure mechanical advance is only for race cars but I'm no expert on the matter!!!

Thanks

Martin
It really comes down to if you are concerned about MPG.

With vacuum advance the car will eek out a mile or so more on longer trips if driving is not "spirited." Properly driven, you will get higher vacuum and thus more total advance if you are just cruising which leads to increased fuel economy.

If the car is used more as a toy and you don't care so much about economy, then the mechanical advance will work just fine by itself. General driveability is not affected. Its been done countless times so it is not just a race car only mod.

Typically you can save a few bucks on the initial purchase if you forego the vacuum advance.
 

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Discussion Starter #3
It really comes down to if you are concerned about MPG.

With vacuum advance the car will eek out a mile or so more on longer trips if driving is not "spirited." Properly driven, you will get higher vacuum and thus more total advance if you are just cruising which leads to increased fuel economy.

If the car is used more as a toy and you don't care so much about economy, then the mechanical advance will work just fine by itself. General driveability is not affected. Its been done countless times so it is not just a race car only mod.

Typically you can save a few bucks on the initial purchase if you forego the vacuum advance.
I understand what your saying but still feel that a Distributor with Vac advance would offer me a few benefits, the problem is I can't find one to suit that has steel gear to go with a roller cam.

Martin
 

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I understand what your saying but still feel that a Distributor with Vac advance would offer me a few benefits, the problem is I can't find one to suit that has steel gear to go with a roller cam.

Martin
That is as easy as knocking the roll pin out holding the gear and swapping them out. Heck think MSD even sales the gears...
 

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For racing you don't need it because you normally have all the mech timing in by 3000. However in cruise mode if you have OD you might be at 2000 rpm so with vacuum you get the timing where it needs to be for power and economy.
 

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+1. There are zero negatives to having vacuum advance, and several positives - even for a racing engine. If in-doubt I'd get it. There is more than MPG to be saved. On a separate note, realize the MSD CDI systems are great for racing, but do not allow the engine to be leaned as much for economy cruise. This is one reason the NASCAR, rally, offshore boats and endurance racers are all dropping it - if they ever used it at all except for sponsorship cash. ;) Again, if in-doubt, I would skip CDI and use single-spark high-energy inductive ignition (IDI) or multi-strike IDI. There are benefits to both CDI and IDI, but the applications are specific for most benefits.

David
 

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Discussion Starter #7
Just got this advice from Steve Slavik at Lunati regarding my Lunati Voodoo Cam..........

"It's on a ductile iron core. The main reason we use those cores is that they are compatible with virtually any distributor gear (as long as it's good quality). Bronze is not required but is an option.

Steve Slavik
Lunati "

That says to me I can use my choice of MSD Distributor which is the 8479 with iron gear. Does anyone disagree with that or have an opinion? I assume that Ductile iron core is esentially some kind of super cast iron and will work with the cast iron gear on the MSD.............I hope!!!

Martin
 

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Correct. Cam --> Gear:

  • Iron --> Iron
  • Steel --> Steel
  • Any --> Bronze
  • Any --> Carbon
  • Any --> Composite
David
 

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I'v been searching for an old Accel or Mallory dist with vac advance and can't find one. Was about to give up the search cause I bout talked myself into the idea that vacuum wasn't really necesary on the street.

Thanks a lot PSIG...now my search continues....LOL
 

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Egg-Bay i'd say....
 

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Period-correct, performance part, and unusual as well? What about this?

David

PS: FE, right?
 

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Period-correct, performance part, and unusual as well? What about this?

David

PS: FE, right?
would be sweeet....except no FE...staying with the stock small block.
Car is all stock and original 289 auto now.

I hate cookie cutter cars...This one is going ot have all the unique vintage stuff I can find, within reason...lol

Kinda stoked right now....I was looking for a set of Moon, SW, guages at the All Ford Superswap in Col...and found...old Autometer underdash guages....After I got home I did a little research...didn't know Autometer had been in business since 1957, thought they were a late '70s company...Another piece of the puzzle found...grinzzzz
 

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Petronix makes a nice billet distro, my shop bought me the non-vac. petronix without asking me which i wanted, but its proven to work very well, without any kind of box to trigger it, which is fine with me.
I don;t know if its just my bad luck but, i;ve had 2 dig. boxes fail me & always at the worst time!
To early to tell if MPG has suffered using the mech.adv. distro
The Petronix billet distro is a simple 2 wire hook up & your off!
 

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Old school gauges equals Steward Warner, Sun.

Accel steel gear equals steel or iron.
 

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I know I would like one of those old style Mallory Unilites with vacuum advance myself. What I liked about that distributor was how easy it was to adjust the mechanical advance with that red key. I had no trouble with that distributor for 5 years when I sold the car.
But I've heard that Mallory and Accel don't have has good of quality parts as they used too. I also heard these units don't keep the timing accurate at high rpm's.

I do hear that MSD is still a good unit with no problems.
 

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I have been running MSD with a programable 6 series box. Works a lot betterr than std mechanical advance. Soon will add a 1 bar map sensor to the mix. This will be like having vacuum advance but more adjustable.
 

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I know I would like one of those old style Mallory Unilites with vacuum advance myself. What I liked about that distributor was how easy it was to adjust the mechanical advance with that red key. I had no trouble with that distributor for 5 years when I sold the car.
But I've heard that Mallory and Accel don't have has good of quality parts as they used too. I also heard these units don't keep the timing accurate at high rpm's.

I do hear that MSD is still a good unit with no problems.
I don't know why, but they are scarce as hens teeth..either thy have all been scrapped, or they are buried so far under the bench no one can find them.

There IS an Accel dual-point on e-bay right now at a good price, not counting the inflated shipping, but it looks pretty rough and I don't have pay-pal.

I'm on the fence about keeping the points, or changing it to a pertronix guts. I'v had good luck with pertronix in the past, but I'v heard bad things lately...on the other hand, points don't leave you dead in the water.
 

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Petronix makes a nice billet distro, my shop bought me the non-vac. petronix without asking me which i wanted, but its proven to work very well, without any kind of box to trigger it, which is fine with me.
I don;t know if its just my bad luck but, i;ve had 2 dig. boxes fail me & always at the worst time!
To early to tell if MPG has suffered using the mech.adv. distro
The Petronix billet distro is a simple 2 wire hook up & your off!
Billet ain't retro tho....I'm about tired of seeing billet this and billet that and billet everything else.....Whats the next trend gonna be I wonder? I hope they get to it soon....
 
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