The Ford Barn

V8COOPMAN · 02-06-2020, 07:55 PM

Quote:

Originally Posted by tubman

I will indulge in a little shameless self-promotion and post a couple of pictures for your approval.

Hell, if we're gonna indulge in some shamelessness, let's do it BIGLY! These things are beautiful, and from all reports that I've seen, bulletproof too! DD

5851a · 02-06-2020, 10:14 PM

I have a side tracked question, on the 3300 series Holley carbs the vacuum secondary's work off of venturi vacuum. Could a person get one of the secondary covers that is made for the dual 4 barrels and use that port on top to feed a Load o matic? I am curious, just wonder if any one has tried it.

chiefdave · 02-07-2020, 08:05 AM

[QUOTE=19Fordy;1849317]

Also, do you know if it's possible to run a stock 53 Ford vacuum advance distributor using a 390 Holley carb. ? I think the vacuum port on the Holley is not below the throttle plates so it won't work but, I'm not sure.
Thanks.

I tried the stock distributor with a 390 Holley and performance was poor. Switched to a Mallory flat top and problem solved. Using the metered vacuum port on the Holley.

tubman · 02-07-2020, 08:27 AM

"chiefdave" - Does your mallory "flattop" have a vacuum advance? I've never seen one for a flathead.

19Fordy · 02-07-2020, 10:04 AM

Tubman: I hope this goes to the correct video. Thanks. I didn't even think about venturi vacuum but, I do recall the port for my Loadamtic dsistributer when it was installed on my stock engine was below the venturi opening. It seems that's what the loadamatic must use to operate correctly. TRUE?https://www.youtube.com/watch?v=Ew1jbxbN9s4

Again, I thank you for your help.

Ol' Ron · 02-07-2020, 10:32 AM

Sponsored Links (Register now to hide all advertisements)

When running a distributor with mechanical advance, you need the vacum advance from the intake manifold to advance the ignition in cruise. This is especially useful in a street engine, improving fuel economy with a lean mixture. Most flathead run rich and this caused accelerated ring ware. the engine rins at light load 90% of the time and should be tuned for it. I run 28 degrees in cruise and 20 at WOT. Seems to run quite well

JSeery · 02-07-2020, 02:01 PM

Quote:

Originally Posted by 19Fordy

I didn't even think about venturi vacuum but, I do recall the port for my Loadamtic dsistributer when it was installed on my stock engine was below the venturi opening. It seems that's what the loadamatic must use to operate correctly. TRUE?https://www.youtube.com/watch?v=Ew1jbxbN9s4

Again, I thank you for your help.

Don't believe so, it uses a combination of sources that attach to the vacuum port. Just looked in the F1 manual, it has a diagram that shows carb vacuum passages. One is from the venturi throat and the other from just above the throttle plate.

tubman · 02-07-2020, 02:28 PM

I knew it had a complex source, but we always just called it "venturi vacuum" when talking Load-a-Matic.

JSeery · 02-07-2020, 02:32 PM

Quote:

Originally Posted by tubman

I knew it had a complex source, but we always just called it "venturi vacuum" when talking Load-a-Matic.

Ya, if it was simple you could probably modify different carbs to work.

I'm not a load-o-matic guy, I'm not even an 8ba guy!!!

chiefdave · 02-07-2020, 03:40 PM

Quote:

Originally Posted by tubman

"chiefdave" - Does your mallory "flattop" have a vacuum advance? I've never seen one for a flathead.

Not really an advance with a dashpot, I've heard it called a vacuum break or vacuum anti-break.

flatheadmurre · 02-07-2020, 04:33 PM

They managed to make it very complicated for using a vacuum control on ford products...a bit of overengineering maybe

tubman · 02-07-2020, 04:59 PM

"chiefdave" - do you mean it has a vacuum brake like a pre-war Ford distributor? I have a Mallory "flattop" for an Olds Rocket that has one of those. It has a vacuum line goes to the distributor and retracts a piston with a leather "puck" on the end, just like a Ford Helmet.

Murre - I think I have that same instruction sheet back in Minnesota, but never had the hardware. I never paid too much attention to it; it's completely different from the system I described above, isn't it?

flatjack9 · 02-07-2020, 05:02 PM

The Mallory does have a vacuum brake like the early Fords which was a Mallory design.

tubman · 02-07-2020, 05:09 PM

It must have been a rare or optional feature, as I have a bunch of "flattops" and the only one with a vacuum brake is the one for the early Olds.

JSeery · 02-07-2020, 06:21 PM

Quote:

Originally Posted by flatheadmurre

They managed to make it very complicated for using a vacuum control on ford products...a bit of overengineering maybe

That doesn't look like fun to deal with! If it was mine, it would become a collector item to hang on the wall and I would look for a different one to run on the engine.

scicala · 02-09-2020, 01:41 PM

Original carbs made to work with Loadomatic distributors supply a blend of vacuum between the venturi suction and ported manifold vacuum. The max the distributor diaphragm will see is maybe 4" hg. With the 390 Holley 4 barrel, as soon as the throttle opens slightly, there will be manifold vacuum to the dist. diaphragm, and wil be a lot more than 4" hg. Therefore, it will more than likely over advance the spark and cause issues. With vacuum to the dist. blocked off, you will only have the base timing setting in all engine modes with extremely hot exhaust temps, not to mention a severe lack of power.

Sal

02-06-2020, 10:14 PM	#22
5851a Senior Member Join Date: Oct 2014 Location: NE Iowa Posts: 1,664	Re: Distributor to 1951 255 8BA I have a side tracked question, on the 3300 series Holley carbs the vacuum secondary's work off of venturi vacuum. Could a person get one of the secondary covers that is made for the dual 4 barrels and use that port on top to feed a Load o matic? I am curious, just wonder if any one has tried it.

02-07-2020, 08:05 AM	#23
chiefdave Member Join Date: Oct 2019 Location: Warsaw, MO Posts: 52	Re: Distributor to 1951 255 8BA [QUOTE=19Fordy;1849317] Also, do you know if it's possible to run a stock 53 Ford vacuum advance distributor using a 390 Holley carb. ? I think the vacuum port on the Holley is not below the throttle plates so it won't work but, I'm not sure. Thanks. I tried the stock distributor with a 390 Holley and performance was poor. Switched to a Mallory flat top and problem solved. Using the metered vacuum port on the Holley.

02-07-2020, 08:27 AM	#24
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,303	Re: Distributor to 1951 255 8BA "chiefdave" - Does your mallory "flattop" have a vacuum advance? I've never seen one for a flathead.

02-07-2020, 10:04 AM	#25
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,925	Re: Distributor to 1951 255 8BA Tubman: I hope this goes to the correct video. Thanks. I didn't even think about venturi vacuum but, I do recall the port for my Loadamtic dsistributer when it was installed on my stock engine was below the venturi opening. It seems that's what the loadamatic must use to operate correctly. TRUE?https://www.youtube.com/watch?v=Ew1jbxbN9s4 Again, I thank you for your help.

02-07-2020, 10:32 AM	#26
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,857	Re: Distributor to 1951 255 8BA Sponsored Links (Register now to hide all advertisements) When running a distributor with mechanical advance, you need the vacum advance from the intake manifold to advance the ignition in cruise. This is especially useful in a street engine, improving fuel economy with a lean mixture. Most flathead run rich and this caused accelerated ring ware. the engine rins at light load 90% of the time and should be tuned for it. I run 28 degrees in cruise and 20 at WOT. Seems to run quite well

02-07-2020, 02:28 PM	#28
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,303	Re: Distributor to 1951 255 8BA I knew it had a complex source, but we always just called it "venturi vacuum" when talking Load-a-Matic.

02-07-2020, 04:59 PM	#32
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,303	Re: Distributor to 1951 255 8BA "chiefdave" - do you mean it has a vacuum brake like a pre-war Ford distributor? I have a Mallory "flattop" for an Olds Rocket that has one of those. It has a vacuum line goes to the distributor and retracts a piston with a leather "puck" on the end, just like a Ford Helmet. Murre - I think I have that same instruction sheet back in Minnesota, but never had the hardware. I never paid too much attention to it; it's completely different from the system I described above, isn't it?

02-07-2020, 05:02 PM	#33
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: Distributor to 1951 255 8BA The Mallory does have a vacuum brake like the early Fords which was a Mallory design.

02-07-2020, 05:09 PM	#34
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,303	Re: Distributor to 1951 255 8BA It must have been a rare or optional feature, as I have a bunch of "flattops" and the only one with a vacuum brake is the one for the early Olds.

02-09-2020, 01:41 PM	#36
scicala Senior Member Join Date: Jun 2010 Location: Detroit suburb, MI Posts: 3,698	Re: Distributor to 1951 255 8BA Original carbs made to work with Loadomatic distributors supply a blend of vacuum between the venturi suction and ported manifold vacuum. The max the distributor diaphragm will see is maybe 4" hg. With the 390 Holley 4 barrel, as soon as the throttle opens slightly, there will be manifold vacuum to the dist. diaphragm, and wil be a lot more than 4" hg. Therefore, it will more than likely over advance the spark and cause issues. With vacuum to the dist. blocked off, you will only have the base timing setting in all engine modes with extremely hot exhaust temps, not to mention a severe lack of power. Sal