The Ford Barn

Notadufus · 05-31-2017, 10:41 AM

I've rebuilt my '49 Ford V8, it's been bored to 257 ci (approx) has a re-ground S-1 Winfield (copy) cam, dual exhausts and 1.6" Chevy valves. It has a Chevy distributor/12V system and it starts and runs better than it ever did before.

I initially started it and broke it in with a single Holley. But, If I remember right, from back in the '50s, that when you switch to dual carbs, a different power valve should be installed. And, maybe different main jets, too.

My question is this: Where can I buy the the right power valves, that will fit these old Holleys?

I've been told that the recently manufactured power valves don't fit right and the engine will not perform well with them.

Any recommendations on the main jets?

Thanx in advance.

chap52 · 05-31-2017, 10:57 AM

I am running dual 94"s and on the advise of CharlieNY on this forum I have blocked off the PV's. He rebuilds carbs and has the dummy pv's for sale. Go to the black bar above the Ford Barn logo on this page, click "Community" and go to page 36, you will be able to pm him from there. I believe that his phone number was recently posted here so you may also "search" CharlieNY to get his number.

JWL · 05-31-2017, 11:21 AM

There is no requirement for blocking the power valves. Actually, the only time this is a completely satisfactory change is when the engine is operated at WOT(wide open throttle). During most other operating conditions the A/F (air/fuel) ratio will be overly rich. I suggest 4.5 or 5.5 power valves for your application with 49 or 50 mains depending on weather, altitude, and driving style.

Bruce_MO · 05-31-2017, 11:43 AM

I bought different power valves and jets for my dual 94 set-up from Daytona Parts... www.daytonaparts.com. They were good to work with and their tech guy was very helpful

adileo · 05-31-2017, 01:45 PM

I with Chap52. When Charlie rebuilt my dual 94s he blocked off the power valves. Car runs great at all speeds.

Notadufus · 06-01-2017, 05:46 AM

Sponsored Links (Register now to hide all advertisements)

Thanx to everyone who sent advice; great response! Now, I have some good info; I will check in with the contacts given, soon. Have a little medical issue, presently, which I hope to get resolved soon.

This is my 3rd flat head Ford, but it's been over 50 years since the last one and I wanna get it right, the first time! I hope to drive this sucker a lot. It should be a blast with the GM 5-speed. (It's going into a '46 Jeep and will be my avatar, when finished)

zzlegend · 06-01-2017, 08:13 AM

My 2 cents. Running dual Holley 94's with 4.5 power valves and 46 jets. Starts and runs perfect.

flatjack9 · 06-01-2017, 09:17 AM

I'm with JWL and zzlegend.

Charlie ny · 06-01-2017, 05:07 PM

Some say tomato some say tamata.
My best results are with the PV's blocked and 49 or 50 jets. Way back when a full compliment of high quality PV's were available things were different. On a day in day out basis the only PV's that meet my reliability test are those from Daytona.......they offer only offer 5.5's and 7.5's. Also from bitter experience 5.5's are too rich. It's not
a case of what I like or hope will work.....it's what DOES work. I ship Flathead goods
all over the country, not just around the corner.
As always I respect everyone's opinions on this and all issues.
Charlie ny

JSeery · 06-01-2017, 05:31 PM

Charlie, what is your approach on a 3 X 2 setup? Block the ends and use a PV in the center, or block all three? This is also considering a heathy cam.

Charlie ny · 06-01-2017, 10:13 PM

J,
I use a 5.5 PV in the center and block the end carbs.
Charlie ny

Kahuna · 06-02-2017, 09:37 AM

What is the logic to block power valves?
Holley, Carter, Stromberg, Rochester, etc. had no idea what they were/are doing?
Correct power valves not available?

JSeery · 06-02-2017, 09:40 AM

See post #9

Kahuna · 06-02-2017, 10:14 AM

??? Post 9
If you remove power valves, and then you say the engine runs great, you must have increased the size of the main jets . In doing so, you have now created an over-rich condition everywhere else.
Power valves are there for a reason.
Maybe removal works for some, but it's not right IMO

Charlie ny · 06-02-2017, 01:56 PM

Kahuna,
A/F about 14.5 to 1 in my testing with a digital A/F gauge with described setup.
It's a blend for sure. If I latched on to some reliable 3.5 PV's and knew I could keep a customer in Iowa or Oregon happy ,well I'd give it shot, for me and them it's a big IF.
Charlie ny

Notadufus · 06-02-2017, 06:58 PM

Good discussion, here. I can see both sides' versions.

I'm gonna try with my two Holley 94s, using power valve plugs. Others, who are using them, report that they run well. I can always install PVs later, if I choose to.

I like the idea of not having to worry about blowing a PV out, in the middle of nowhere.

Pete F · 06-05-2017, 05:39 AM

If your running both carbs together run the power valves .
Power valves get a bad wrap because most times people don't install the proper vacuum set valves and either open to soon or to late.
The propose of the valve is to richen the mixture under load so if they open late the engine starves if they open early the engine runs rich so the proper valve is important and also the proper jetting to work in combination with the valve is equally as important.
By blocking the circuit it's easier to jet but not as efficient as a setup with valves.
If you are running a multi carb setup with dump carbs than block the valves on the dump carbs because they are only used for wide open throttle and use the valve on the primary carb.
The valves have been Holley bad wrap from day one till today's carbs because it takes a little patience to get the balance but they work fine when you understand them.
I have been building carbs of all kinds my whole life so I'm talking from experience.

Sent from my iPad using Tapatalk

Init1 · 06-05-2017, 08:08 AM

I too have been through this. After many changes I finally got good results. I have a 276 c.i with a 3/4 cam. It now runs good with 4.5
Power Valves and .51 mains. I also use NGK
Plugs that seem to stay cleaner than Champion, AC or Motorcraft.
And remember basically the bigger the
displacement and cam the more gas you need.

05-31-2017, 10:41 AM	#1
Notadufus Junior Member Join Date: Oct 2015 Location: Florida Posts: 17	Holley 94 jetting/power valve for dual carbs I've rebuilt my '49 Ford V8, it's been bored to 257 ci (approx) has a re-ground S-1 Winfield (copy) cam, dual exhausts and 1.6" Chevy valves. It has a Chevy distributor/12V system and it starts and runs better than it ever did before. I initially started it and broke it in with a single Holley. But, If I remember right, from back in the '50s, that when you switch to dual carbs, a different power valve should be installed. And, maybe different main jets, too. My question is this: Where can I buy the the right power valves, that will fit these old Holleys? I've been told that the recently manufactured power valves don't fit right and the engine will not perform well with them. Any recommendations on the main jets? Thanx in advance.

05-31-2017, 10:57 AM	#2
chap52 Senior Member Join Date: Jun 2013 Location: Marana Arizona Posts: 1,776	Re: Holley 94 jetting/power valve for dual carbs I am running dual 94"s and on the advise of CharlieNY on this forum I have blocked off the PV's. He rebuilds carbs and has the dummy pv's for sale. Go to the black bar above the Ford Barn logo on this page, click "Community" and go to page 36, you will be able to pm him from there. I believe that his phone number was recently posted here so you may also "search" CharlieNY to get his number.

05-31-2017, 11:21 AM	#3
JWL Member Emeritus Join Date: May 2010 Location: Fitzgerald, Georgia Posts: 2,204	Re: Holley 94 jetting/power valve for dual carbs There is no requirement for blocking the power valves. Actually, the only time this is a completely satisfactory change is when the engine is operated at WOT(wide open throttle). During most other operating conditions the A/F (air/fuel) ratio will be overly rich. I suggest 4.5 or 5.5 power valves for your application with 49 or 50 mains depending on weather, altitude, and driving style.

05-31-2017, 11:43 AM	#4
Bruce_MO Senior Member Join Date: May 2010 Posts: 433	Re: Holley 94 jetting/power valve for dual carbs I bought different power valves and jets for my dual 94 set-up from Daytona Parts... www.daytonaparts.com. They were good to work with and their tech guy was very helpful

05-31-2017, 01:45 PM	#5
adileo Senior Member Join Date: Jun 2014 Location: New Jersey Posts: 1,772	Re: Holley 94 jetting/power valve for dual carbs I with Chap52. When Charlie rebuilt my dual 94s he blocked off the power valves. Car runs great at all speeds. __________________ Thanks Andy 1952 F1

06-01-2017, 05:46 AM	#6
Notadufus Junior Member Join Date: Oct 2015 Location: Florida Posts: 17	Re: Holley 94 jetting/power valve for dual carbs Sponsored Links (Register now to hide all advertisements) Thanx to everyone who sent advice; great response! Now, I have some good info; I will check in with the contacts given, soon. Have a little medical issue, presently, which I hope to get resolved soon. This is my 3rd flat head Ford, but it's been over 50 years since the last one and I wanna get it right, the first time! I hope to drive this sucker a lot. It should be a blast with the GM 5-speed. (It's going into a '46 Jeep and will be my avatar, when finished)

06-01-2017, 08:13 AM	#7
zzlegend Senior Member Join Date: May 2010 Location: Reseda, Calif. Posts: 2,188	Re: Holley 94 jetting/power valve for dual carbs My 2 cents. Running dual Holley 94's with 4.5 power valves and 46 jets. Starts and runs perfect.

06-01-2017, 09:17 AM	#8
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,527	Re: Holley 94 jetting/power valve for dual carbs I'm with JWL and zzlegend.

06-01-2017, 05:07 PM	#9
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Holley 94 jetting/power valve for dual carbs Some say tomato some say tamata. My best results are with the PV's blocked and 49 or 50 jets. Way back when a full compliment of high quality PV's were available things were different. On a day in day out basis the only PV's that meet my reliability test are those from Daytona.......they offer only offer 5.5's and 7.5's. Also from bitter experience 5.5's are too rich. It's not a case of what I like or hope will work.....it's what DOES work. I ship Flathead goods all over the country, not just around the corner. As always I respect everyone's opinions on this and all issues. Charlie ny

06-01-2017, 05:31 PM	#10
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Holley 94 jetting/power valve for dual carbs Charlie, what is your approach on a 3 X 2 setup? Block the ends and use a PV in the center, or block all three? This is also considering a heathy cam.

06-01-2017, 10:13 PM	#11
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Holley 94 jetting/power valve for dual carbs J, I use a 5.5 PV in the center and block the end carbs. Charlie ny

06-02-2017, 09:37 AM	#12
Kahuna Senior Member Join Date: May 2010 Location: NorCal Posts: 2,617	Re: Holley 94 jetting/power valve for dual carbs What is the logic to block power valves? Holley, Carter, Stromberg, Rochester, etc. had no idea what they were/are doing? Correct power valves not available?

06-02-2017, 09:40 AM	#13
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Holley 94 jetting/power valve for dual carbs See post #9

06-02-2017, 10:14 AM	#14
Kahuna Senior Member Join Date: May 2010 Location: NorCal Posts: 2,617	Re: Holley 94 jetting/power valve for dual carbs ??? Post 9 If you remove power valves, and then you say the engine runs great, you must have increased the size of the main jets . In doing so, you have now created an over-rich condition everywhere else. Power valves are there for a reason. Maybe removal works for some, but it's not right IMO Last edited by Kahuna; 06-02-2017 at 10:24 AM.

06-02-2017, 01:56 PM	#15
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Holley 94 jetting/power valve for dual carbs Kahuna, A/F about 14.5 to 1 in my testing with a digital A/F gauge with described setup. It's a blend for sure. If I latched on to some reliable 3.5 PV's and knew I could keep a customer in Iowa or Oregon happy ,well I'd give it shot, for me and them it's a big IF. Charlie ny

06-02-2017, 06:58 PM	#16
Notadufus Junior Member Join Date: Oct 2015 Location: Florida Posts: 17	Re: Holley 94 jetting/power valve for dual carbs Good discussion, here. I can see both sides' versions. I'm gonna try with my two Holley 94s, using power valve plugs. Others, who are using them, report that they run well. I can always install PVs later, if I choose to. I like the idea of not having to worry about blowing a PV out, in the middle of nowhere.

06-05-2017, 05:39 AM	#17
Pete F Senior Member Join Date: Feb 2017 Location: Bloomfield,ny Posts: 130	Re: Holley 94 jetting/power valve for dual carbs If your running both carbs together run the power valves . Power valves get a bad wrap because most times people don't install the proper vacuum set valves and either open to soon or to late. The propose of the valve is to richen the mixture under load so if they open late the engine starves if they open early the engine runs rich so the proper valve is important and also the proper jetting to work in combination with the valve is equally as important. By blocking the circuit it's easier to jet but not as efficient as a setup with valves. If you are running a multi carb setup with dump carbs than block the valves on the dump carbs because they are only used for wide open throttle and use the valve on the primary carb. The valves have been Holley bad wrap from day one till today's carbs because it takes a little patience to get the balance but they work fine when you understand them. I have been building carbs of all kinds my whole life so I'm talking from experience. Sent from my iPad using Tapatalk

06-05-2017, 08:08 AM	#18
Init1 Senior Member Join Date: May 2010 Location: Oregon City, Oregon Posts: 208	Re: Holley 94 jetting/power valve for dual carbs I too have been through this. After many changes I finally got good results. I have a 276 c.i with a 3/4 cam. It now runs good with 4.5 Power Valves and .51 mains. I also use NGK Plugs that seem to stay cleaner than Champion, AC or Motorcraft. And remember basically the bigger the displacement and cam the more gas you need.