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By Philip - 10 Years Ago
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I'm building a set of Holly 4000-1434 carbs for my 312 T.B. engine. The engine has been bored 60 over with a Isky 300 cam, G heads and the correct 3 speed OD trany. I'm replacing a pair of 1437's which I couldn't idle below 1000 RPM. My first question is about the throttle plates. I read that Ted said a good way to check the plate alignment was to put a light behind and check the bores. The shaft bushings seem to be tight and the plates centered and move freely, but when shinning the light through there is a minimum amount of visible light. Would this be acceptable or should there be zero light visible? Some of the screws would have to be drilled out to replace the bushings. My second question is about jet size. According to Gill a T.B. professor, the #'s for the primary main jet is # 45, secondary jet # 55 and the power jet # 32 and use the yellow secondary throttle diaphragm springs. Are these the right #'s for my engine specs? Third question is about using dashpots on this setup. Should there be one, two or no dashpots with the OD trany? After reading all the Q&A on this forum this is an excellent place to look for answers. Thanks for any input you might have. Philip
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By Dobie - 10 Years Ago
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There is should be a small bleed past the throttle plates for idle air, hence the slivers of light you're seeing. To my knowledge no dashpots were used with manual transmissions, only automatics. Can't say about the jet sizes and secondary springs but I'm sure someone will chime in soon with that info.
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By Oldmics - 10 Years Ago
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No dashpot on stick cars.
Jet sizes , power valve size and springs you mention are all correct for a stock engine.
Are these correct for your modified engine requirements? Only your hair dresser knows for sure !
If it were mine, I would say probably not. But I'm sure its in the ball park enough to run reasonably well.
Oldmics
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By Ted - 10 Years Ago
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Keep in mind that the jetting for the factory dual quad carbs will not be applicable to single four barrel Teapots being retrofitted for dual quad applications. This is in part due to the single four carbs being larger in cfm than the original dual quad carbs and this in turn simply requires larger jets in which to compensate for the larger primary venturies. Air bleed sizing in the fuel bowl cover plate is also a player in that the air bleeds have much to do with the overall fuel curve. Different air bleed sizing requires different jet sizing. The fuel bowl cover plates are numbered and those numbers can be used to track down the air bleed sizing as originally delivered. As John brings up, any engine modifications will also affect the jetting.
Anytime two carbs are used, the vacuum signal through each is reduced in half and with this in mind, the secondary spring tension should be reduced in half. The yellow springs available in the Holley spring kit are suitable for this. I tend to use the short yellow spring for these conversions but the long yellow spring does a better job in closing the secondary blades more solidly when the secondary circuits are not being used. I make it a point to use similarly numbered fuel bowl covers so that the air bleed sizing is consistent with both carbs.
I target for zero light through the bores when the idle screws are backed up completely. The secondary blades should also have zero light and if there is light is showing through on those, then it becomes difficult to get the idle back down to where it needs to be.
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By Philip - 10 Years Ago
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I've received 3 good post to my carburetor problems which I am grateful. When I purchased the car in 1980 it ran well for a tired engine. Between 1957 and 1970, because of the cam change, rear stabilizers and OD modifications I believe it had a hard life as a street or drag strip car. When we rebuilt the engine in 2012 it had a stock bore but had to machined .60 over to clean it up. The Esky 300 cam ran and sounded good so I sent it to be checked out and had one of the lobes rebuilt. After putting 200 miles on the engine it runs very well with the exception of the high idle and 25# oil pressure at idle. I use 10W40 Rotella oil.
My follow up question: The car should have left the factory with 1434 carbs but had a pair of 1437s. We rebuilt the 37s and maybe didn't refine our work enough causing the high idle. I have a pair of rebuildable1434 carbs and what jetting sizes if any would be appropriate for the engine modifications?
It was important to know the throttle body light test should be close to zero, especially the secondary's to reach idle specs. The fuel bowl covers each have the same #s which I didn't realize was important. This post was very important for a positive rebuild. Thanks again, Philip
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By DryLakesRacer - 10 Years Ago
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From my experience with other carbs and multi carb setups jetting should only be changed from stock when compression ratio is increased. Are you planning to use the setup as Ford did with both carbs working in unison or going possibly to a progressive set up?
If progressive it seems to me you could convert the Holley's to use a centrifugal distributor as shown to us by Ted and Idle on both but run on the primaries of the one where the primaries are most central to the engine . On this site guys guys have run them forward (non-stock) and backwards like original.
I run my dual 4 barrel carbs on my 292 (not Holley's) with stock compression and cam; a progressive set-up and am extremely happy with idling and running.They do not use vacuum secondaries. Both carbs are only 1/4 turn from fully closed on the Idle and the mixtures are just about the same as when I had a single 4 barrel. Both have the original size jets they were manufactured and the were sized to an engine with 9 more cubic inches and and 8-1 compression instead of the Fords 8.4-1.
Good Luck... This is indeed the best place to get answers....................
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By Philip - 10 Years Ago
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Because this car was an original E model I'm keeping it as much original as possible. In my opinion Ford didn't have a better idea when they set the carburation up to work in unison. The progressive carb option would have been easier to tune with better gas mileage for street use. The car ran real good with the 1437s on so I'll probably use the factory size jetting in the 1434s. Thanks for your opinion on the carbs. Philip
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By slumlord444 - 10 Years Ago
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Ted, do you happen to know the CFM ratings for the '56 single 4 barrel carbs and the E carbs? You mention jetting issues because of the CFM difference. When I first put my E set up on my '57 Bird in '66 I used two '56 Ford single carbs and used the dual quad jetting from the '62 Hot Rod Ford Performance Manual. Put screws in the linkage to manually open the secondary's. Ran fine for many years. A little touchy off the line with the manual secondary's but it worked until I got a set of the E carbs. .
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By Lord Gaga - 10 Years Ago
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Philip (1/13/2015)
I've received 3 good post to my carburetor problems which I am grateful. When I purchased the car in 1980 it ran well for a tired engine. Between 1957 and 1970, because of the cam change, rear stabilizers and OD modifications I believe it had a hard life as a street or drag strip car. When we rebuilt the engine in 2012 it had a stock bore but had to machined .60 over to clean it up. The Esky 300 cam ran and sounded good so I sent it to be checked out and had one of the lobes rebuilt. After putting 200 miles on the engine it runs very well with the exception of the high idle and 25# oil pressure at idle. I use 10W40 Rotella oil. My follow up question: The car should have left the factory with 1434 carbs but had a pair of 1437s. We rebuilt the 37s and maybe didn't refine our work enough causing the high idle. I have a pair of rebuildable1434 carbs and what jetting sizes if any would be appropriate for the engine modifications? It was important to know the throttle body light test should be close to zero, especially the secondary's to reach idle specs. The fuel bowl covers each have the same #s which I didn't realize was important. This post was very important for a positive rebuild. Thanks again, Philip
Nice looking engine. What body is it in? Do you have the Isky RPM 300 or F 300 cam? I have the RPM 300 advanced 4 deg. in my 312 and like it a lot. My car has 20 Lbs. oil pressure at 800 rpm hot idle. Not to worry, no problem.
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By Ted - 10 Years Ago
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slumlord444 (1/15/2015)
Ted, do you happen to know the CFM ratings for the '56 single 4 barrel carbs and the E carbs? You mention jetting issues because of the CFM difference. .........
I’ve used 410 cfm as the number for the single four barrel Teapot carbs. Keep in mind that two of these would likely not be 820 cfm but some number less than this simply due to the reduced air flow in having two of these working together. As camming, cubic inches, and/or the compression ratio changes, then jetting also changes. The factory jetting was simply for the factory combination but is a good starting point for an unknown combination when no other information is available.
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By Philip - 10 Years Ago
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The cam is a ISKY RPM 300 and was in the car when I purchased it. I sent it out to have the lobes checked instead of replacing it because I like you, loved the way it preformed and sounded. It's probably not the best for racing but it's a great street engine cam. I maybe could find the specs for it if I went through all my paper work. The engine is in a factory E Bird. The engine and the carbs were powder coated. Coating the carbs may be some of my idle problem but I'm power coating the 1434's that I'm rebuilding being a little more precise. My concern with PC the engine was that it may run hotter but it seems just the opposite. This may be because the block casting is porous and the coating is smooth keeping it cleaner and letting more air move over the block. My engine idle is high and the oil pressure may go on the south side of 20 if the idle is near 500. I may try 10W50. I hope I'm not getting too far off this post topic. Philip
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By Ted - 10 Years Ago
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Philip (1/15/2015)
........ My engine idle is high and the oil pressure may go on the south side of 20 if the idle is near 500. I may try 10W50. I hope I'm not getting too far off this post topic. .....
There’s absolutely nothing wrong with 20 psi oil pressure at 500 rpms.
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By Philip - 10 Years Ago
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In rebuilding a pair of 9510 AB - List 1434 carbs the kits didn't have the right needle and seats. Number 110 seats and ball tip needles came out of the carbs. The seats in the rebuild kits were unmarked but seemed to be larger with the pointed needles. I do have 2 new needle and seat kits. One is # B6A-9564-A with the ball tip needle and #110 on the seat. The other is a pointed tip needle and # 97-S on the seat. The B6A kit with the #110 seat is probably a little smaller than the 97-S seat kit. Will these kits work ok on the e setup? My second question is for the best performance and IDLE, if I use this combination, which would be the best to use for the front carb or wouldn't it make any difference? This is a unison setup. Thanks for any input. Philip
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By NoShortcuts - 10 Years Ago
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I'm unable to answer your most recent question, Philip.
What follows is a source of quality carburetor component parts. The last I knew, there was no minimum order with this company, which is unusual with most suppliers. The parts this company is producing are often what you'll find supplied in other retail vendors 'kits'.
https://buy.walkerproducts.com/carburetor/components/ford/ford-4bbl-4100-3-carburetor-components.html
Hope this may help you going forward. 
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By Philip - 10 Years Ago
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Thanks for your last reply. The problem with the needle and seats that came in the rebuild kits were they were treaded and would not fit down in the bore. On the problem solving section of their web site they said the treaded seats would work, which they won't, or use the old seats with the new needles. I went on e-bay and found one seat and needle kit from Motorcraft, B6A-9564-A. I just found the second kit and I now have a matched pair with the original seat numbers. The needles have the ball tips while the rebuild kits had the pointed neoprene tips. Its a silly question because I know either will work but wonder why they went from the ball to the neoprene? I can now proceed rebuilding these two carb and don't expect any more problems, but if I do I know the best place to get good answers. Thank you, Philip
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By Ted - 10 Years Ago
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I've come across the 1434 & 1437 carbs with both the spring loaded and threaded needle seats. The carb kits from Daytona Carb Parts come with both styles of seats but many other kits seem to come only with the threaded seats. In those cases, I simply thread the fuel bowl body for the threaded seats. This is especially helpful when one carb is spring loaded and the other is threaded. This puts both seats being the same.
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By Philip - 10 Years Ago
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 I recently installed my rebuilt carbs and started the engine. After priming the carbs with an electric fuel pump the engine turned over 3 times and started right up. the problem is the tack went up to 2200 RPM's and that's as low as I can get it to idle. When installing the carbs I synchronized and checked the linkage making sure the fast idle cam was not the problem. I had a small fuel leak under the needle seat plug and didn't use the springs because I tapped and threaded the seats. I tried adjusting the idle adjusting needles which did nothing. With all the help I received from this site and a video I felt confident the rebuild went well. I used a smoke machine from snap on to check for vacuum leaks trying to get my previous carb setup down to 1000 RPM's and this set is worse. Check the link of the rebuilt 1434 carbs. I'm stumped and any ideas will be appreciated. Philip in Ohio
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By charliemccraney - 10 Years Ago
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If it will not idle lower than 2200, then it is getting air somewhere. It simply won't idle that high, otherwise. How well does a smoke machine work for areas which are difficult to see, like under the intake, or behind the carburetors? I would check again using starting fluid, where you will notice a change in the way the engine runs if a leak is found. If no leaks are found, maybe the primary or secondary throttle plates are opened farther than they should be for some reason.
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By NoShortcuts - 10 Years Ago
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Hmmmm... As Charlie says, 2200 rpm is sky high. You've got to have a BIG air leak somewhere to feed that engine speed. Be careful in using that starter fluid!
I've used standard viscosity engine oil applied with a pump oil can around the base of carbs as a way to find where air is getting into the system. IF the oil temporarily seals the leakage, the idle speed drops. Check for other potential vacuum leaks to the engine including power brake connections to the intake manifold and the line to the double diaphragm fuel pump. A faulty vacuum booster diaphragm on either of these components would show as a vacuum leak. Potentially, you could have more than one vacuum leak source working together to give you this high an idle speed.
Also check...
- all throttle plates fully closed (seated)... right?
- with the 'E' 'Bird set-up, you've got 1/8 inch aluminum spacers in a gasket sandwich under the carbs on the aluminum intake manifold... right?
- distributor vacuum line connected from the rear carburetor to the distributor advance chamber... right?
- distributor vacuum advance take-off on the front carb blocked off with a plug... right?
- No spark control valves on your 'E' carbs... right? (Spark control valves on other Holley 4000 carbs have a diaphragm in them that can leak)
- Vacuum control secondary diaphragm units are gasket-ed to the carburetor aluminum bases... right?
- Neoprene hose connecting the take-off from the carb bases for the secondary vacuum signal balance tube... right?
OUCH! Scratching my head for other ideas...
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By NoShortcuts - 10 Years Ago
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Don't I recall a gasket for the vacuum secondary diaphragm housing where it mounts on the Holley 4000 carburetor base that can be incorrectly positioned because of it having an extra hole or it being a gasket that can be reversed for mounting, but will not work correctly if incorrectly positioned???
Still scratching my head on your LARGE vacuum leak!
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By Philip - 10 Years Ago
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 From the replies it seams pretty obvious it has to be a vacuum leak. I borrowed a smoke machine to get my first set of carbs below 1000 RPM's and couldn't find any problems. This set I thought I'd try a small propane bottle with a rubber hose on the end to check all the gaskets. Using oil in a pump can should also work but might be a little messy. Your check list was good:
1- In the rebuild I paid special attention all the throttle plates worked freely and were as tight as possible. Is it possible to check them with the carb assembled?
2- I think the carb spacers are right. I used the same ones that were under the other set of carbs but I couldn't get those under 1000 RPM.
3- Distributor line is connected.
4- The front distributor port is plugged.
5- No spark advance on the E carbs.
6- I didn't seem to have a problem with the gaskets on the secondary diaphragm units.
7- I used a rubber hose to connect the carb bases, which are tight.
The car doesn't have power brakes but I better check the wiper hose under the dash. The fuel/vacuum pump was rebuilt and shouldn't be a problem. Does the propane rubber hose procedure seem like a good way to check for the vacuum leak as this has to be my way forward. Thanks for all the potential items to look at as this was very helpful.
The front air cleaner stud on the first picture sure looks crooked, but it must be the picture angle. I'm sending a picture of the other side for possible problems. It may be awhile but I'll let you know what I found out. Thanks again, Philip in Ohio
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By charliemccraney - 10 Years Ago
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Don't think the carb spacers are right. Check them and know that they are right. Pull the carbs and make sure the spacers and gaskets are sealing properly against the intake and carburetors. Also make sure that the spacers are not causing the throttle plates to stick open somehow.
It sounds like you rebuilt the carbs in an attempt to fix the 1000rpm idle problem and now it idles at 2200. If everything else is the same, then something you did during rebuild may have caused it to pick up an additional 1200rpm. Revise your rebuild. Can you run one carb at a time to se if you can track it to one carb or the other, or simply to get it running right with one carb and then moving on to the next?
I think the lens of your camera is distorting the image and making things look crooked.
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By NoShortcuts - 10 Years Ago
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I'm STILL scratching my head on your problem. This is a long shot, but was raised some time ago by Oldmics. Something is giving you serious air to support 2,200 rpm. Look at these directions and check your linkage before tearing anything else down.
Hope this helps. 
_______________________
Here are the instructions from the 1957 National Service Data book. Also check the TSB (product service letters) book on page 140. It pretty much spells out the same information. The specific PSL is P 348. Oldmics
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By Philip - 10 Years Ago
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Good morning, I have the product service manual and have the carbs set up as specified. I put new gaskets under the carbs. top and bottom, but used the old spacers that were on the car from the past. This may be the problem. I can't believe there is a problem with the carbs as I was real picky rebuilding them. I need to find more info on the carb spacers first and proceed through the list of potential items you gave me. At the top of my list is to check for the vacuum leak with the torch and rubber hose or borrow the smoke machine again. The problem is so bad it should be easy to find. Thanks again for all the help. Philip in Ohio
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By Ted - 10 Years Ago
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Were the throttle blades removed from the shafts during the rebuild? Those can be very touchy when reinstalling them in order to get them all seated in a fully closed position. If you can see any light at all with the throttles fully closed, then the blade adjustments on the shafts will need to be revisited.
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By Philip - 10 Years Ago
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I can look down and see the secondary throttle plates are closed and working properly. I didn't take them out but loosen them up to fine tune them. I spent a lot of time adjusting them with the light to get the tolerance near zero. Next week I'm going to do a vacuum test to see where the problem is before taking anything apart. If it's the carb spacers I'll order new ones. You guys have been great. Happy Easter, Philip in Ohio
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