single carb distributor question

[4tford]

Customer would like to know if he can run a stock dizzy on his engine. 8ba, .040 over bore, merc 4 " crank and L-100 cam. He wants the external to look as stock as possible on his truck. Thanks Bill

[rotorwrench]

The cam is the thing that is going to gum the works and also carburetor since the stock advance won't work without a stock 8BA or Holley 885 unit. The OEM unit is just barely adequate even in stone stock applications.

I would suggest a modified GM distributor or maybe a Chrysler unit with both centrifugal and vacuum advance. This would allow for much better performance and fuel economy. Bubba and other flathead ignition repair folks do these mods.

[flatjack9]

The number of people that look at the engine and actually know what it should look like is very small. I'd be more concerned how my engine ran.

[Ol' Ron]

Rotorwrench is right, the L-100 has 245 degs of duration @ .050" lift. I doubt the dist would even work. Now do you have the piston to head clearance closed up? This is a great cam if you do the right mods, it need s compression.

[34PKUP]

Originally Posted by Ol' Ron

Rotorwrench is right, the L-100 has 245 degs of duration @ .050" lift. I doubt the dist would even work. Now do you have the piston to head clearance closed up? This is a great cam if you do the right mods, it need s compression.

Even if the distributor gets it's vacuum signal from the carb. venturi and not the manifold?

[Krylon32]

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Check out the modified Chevy distributor that Bubba makes, it may work better for you. I've used several and they work great.

[scooder]

Originally Posted by 34PKUP

Even if the distributor gets it's vacuum signal from the carb. venturi and not the manifold?

You can't run a loadamatic from the intake vacuum. Completely the wrong signal to the ignition.
The L100 cam isn't compatible with a loadamatic, I've tried. The advance curve just ends up wrong and all over the place.
Martin.

[scooder]

Originally Posted by 4tford

Customer would like to know if he can run a stock dizzy on his engine. 8ba, .040 over bore, merc 4 " crank and L-100 cam. He wants the external to look as stock as possible on his truck. Thanks Bill

If he's running stock heads that cam is going to be lame, as Ron said, the L100 needs high compression, without it the engine is not nice, the around town torque is not as good as a stock cam. Give it some compression and it will come alive! Really alive! I know I've done it.
You won't get the required compression with milled stock heads, the valves often touch a stock head, so cutting the heads will need the valve area cut deeper, you can see this won't get you very far.
I'm not saying it lightly, low compression + L100 cam is wasting time and money. I've been through the stock cam, drove like a Flathead, then a couple of carbs on top, oooh gota bit more poke up top, then pop the L100 in, eah? Must be a dodgy cam, disappointing, ok up top, bugger all down low. Then pull the stock heads and bung on some Navarro 9.75:1 planks!!!! God damn!!! Really! Holy #@#@ this my friend is a hot rod!!
This is my opinion based on the above experience.
If anybody is running this cam, or a similar spec cam with stock compression, and you think it's good, trust me, put a pair of high compression heads on it and get the ignition optimized, you will be amazed, truly amazed. It nearly made my little brother puke when I first nailed the foot feed.
Martin.




High compression.

The only way.

[34PKUP]

Originally Posted by scooder

You can't run a loadamatic from the intake vacuum. Completely the wrong signal to the ignition.
The L100 cam isn't compatible with a loadamatic, I've tried. The advance curve just ends up wrong and all over the place.
Martin.

The Loadamatic gets it's signal from the carb. venturi not the intake manifold. So that won't work?

[JSeery]

Originally Posted by 34PKUP

The Loadamatic gets it's signal from the carb. venturi not the intake manifold. So that won't work?

Not totally a true statement, the load-a-matic uses a special carburetor designed to work with it. It does not just run off of "venture" vacuum.

[34PKUP]

Originally Posted by JSeery

Not totally a true statement, the load-a-matic uses a special carburetor designed to work with it. It does not just run off of "venture" vacuum.

Then you are saying that it gets a vacuum signal from another source?
Please enlighten those of us who don't have the knowledge.

[rotorwrench]

The Holley Load-O-Matic system uses a dual port balance vacuum signal and only moves at a snails pace against spring tension. One of the ports is just above the throttle plate and it is joined by a common passage with another port in the venturi. The carb & distributor were both a Holley product and designed to be just "Good Enough" for stock applications. The old mallory design crab distributor was better by far but they had just changed over to the side mounted design and didn't do much shopping around for a better unit at the time.

[BUBBAS IGNITION]

Originally Posted by 4tford

Customer would like to know if he can run a stock dizzy on his engine. 8ba, .040 over bore, merc 4 " crank and L-100 cam. He wants the external to look as stock as possible on his truck. Thanks Bill

The basic question is ? Will the load a matic work in this application??
The answer is NO it will not work.
There are many different ways to get this replaced with a mechanical advance distributor.
New Mallory unit
Old school Mallory unit
Chevrolet conversion with mech advance curve

The easiest and most practical has been the chevrolet conversion. They sell for $250 plus shipping...

[flatjack9]

I'm sure Bubba makes a nice unit, but I would also check with Charlie, NY. I've used a number of his distributors and they are top notch.

[tubman]

At first blush, I would have guessed it would probably work, but I have never tried it. After reading "Scooder's" reply, I would advise strongly against it; he knows what he's doing and has obviously been down this road before.

[flatjack9]

The plain truth is, not that many people even know whether their engine is running efficiently or not. I'm sure some would be surprised by the results if they got rid of the Loadamatic. I also strongly suggest to get the distributor that has mechanical as well as vacuum advance.

[4tford]

Customer wants the stock heads to stay. He will talk to Bubba when he gets closer to install. Thanks guys.

[scooder]

Shame, Big shame. He genuinely won't get the benefit from that cam. A 1007 would probably suit him more. Youd be able to cut the heads for a not of compression with that one.
The L100 is a cracking cam, I love um, but this is a classic case of a parts miss match.
Martin.

[flatheadmurre]

Closest to stock look with some compression would be a cut set of EAB heads.
Does he want the heads saying 8BA or just a set of original cast iron...
If going for L-100 stock isnt exactly what comes to mind.
But a set of milled EAB heads and a big 97 with some porting of the intake would make it move still looking fairly stock.

[51 MERC-CT]

Another option for a stock size/looking distributor would be a modified Mallory that was intended for a Chev. or small block Mopar. This will give the use of manifold vacuum.