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Brand new Zenith updraft carbs


Tonz
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My '26 Chrysler currently has a Tillotson JR4, nice looking carb with no apparent wear or damage, but a bit dodgy with sticking float and fuel leak, and it's 1/4" is larger in size. So I'm not feeling safe with it.

But I have seen these Zenith replacements on eBay and word is they are a quality carb. 

Has anyone had experience with them or recommend a "new" carb.

Thanks

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Basically.......it’s agreed by most members here, changing carburetors is almost always a bad idea for five hundred good reasons.........

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I use one on a model A ford now and it works without troubles. it is important that the carb works for the size of your engine. I use an autolite carb from a 200 CI Ford on my 206CI Chevy 6 engine and it works better than the old Carter that was on it. Experiment and have fun. I once built a Zombie carb out of Pontiac, Zenith, Tillotson, and Autolite carb parts for my model A and it worked very well. I just like to play!

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I used one on my 1910 EMF and it ran flawlessly. Getting the original brass carburetor running was  not going to happen, due to warped brass castings. Since EMF used it's own carburetor, spare parts were made of unobtainium...  Sure, it was not original, but it kept one more old car on the road, even if "it’s agreed by most members here, changing carburetors is almost always a bad idea for five hundred good reasons."

 

Frank

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A replacement carburetor of a quality manufacturer that WAS ENGINEERED SPECIFICALLY FOR YOUR ENGINE is not necessarily a bad idea.

 

A replacement carburetor, even from a quality manufacturer, that is a universal "one size fits all, works well on none" is NOT a good idea.

 

A cheap replacement carburetor from somewhere from an unknown manufacturer is never a good idea.

 

Zenith is a quality manufacturer, but many of their offerings are for fixed RPM engines; how many gears are in your transmission?

 

Jon.

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12 hours ago, oldford said:

I used one on my 1910 EMF and it ran flawlessly. Getting the original brass carburetor running was  not going to happen, due to warped brass castings. Since EMF used it's own carburetor, spare parts were made of unobtainium...  Sure, it was not original, but it kept one more old car on the road, even if "it’s agreed by most members here, changing carburetors is almost always a bad idea for five hundred good reasons."

 

Frank

 

 

From one of the leading carburetor experts in the world Frank............ and I manufacture 150 parts for Stromberg carburetors. I have probably only rebuilt 700-800 carburetors and have 40 years experience in pre war cars, Jon has rebuilt tens of thousands and has done more historical research on them than anyone I am aware of. If yo don't have a chassis dyne, a five gas analyzer, and an ignition scope.......how do you know your car is running fine? 

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9 hours ago, edinmass said:

 

 

If yo don't have a chassis dyne, a five gas analyzer, and an ignition scope.......how do you know your car is running fine? 

From you comments, I obviously don't know that my car runs fine. I do know, after nearly 50 years in this hobby, and countless numbers of cars that I have owned, that my cars move along the road as they should without overheating, flooding, vapor lock, timing knock, etc. While I don't have nearly the experience or the knowledge that you possess, I have enough knowledge to keep me out of trouble, which is all I'm looking for.

 

Frank

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Zenith makes carburetors WITH power circuits, and carburetors WITHOUT power circuits.

 

The carburetors WITH power circuits normally sell for about 3 times the price of the ones without.

 

The ones W/O, IF PROPERLY SIZED to the airflow of the engine; CAN work fairly well in FLAT terrain.

 

Do not confuse the power circuit with the adjustable main metering jet, which only can adjust the main metering circuit. The power circuit, when present, will augment the fuel supplied by the main metering circuit when the operator calls for additional power (climbing a grade, etc.).

 

Many enthusiasts seem to rate a replacement carburetor if/if not the carburetor has an accelerator pump. Very few low compression engines with updraft carburetors will benefit from an accelerator pump. If fact, a true accelerator pump (rather than a vacuum pump) is NOT a good idea. The true accelerator pump is one of two gripes I have with the Carter BB-1.

 

And granted, many early carburetors did not have power circuits, and they did run, however, they may run significantly better with the power circuit.

 

The thing to remember when making changes (I don't buy the universal modern buzzword "upgrade", many are "downgrades"), is that each component should be ENGINEERED to the overall function of the engine. A modern Holley Dominator 4-barrel is NOT going to improve the horsepower of an otherwise stock Model A Ford engine. This may sound like a ridiculous example, and it is; but I get calls from enthusiasts every telephone day that are almost as ridiculous.

 

A new, made by some unknown maker, "carburetor", with a 32 mm venturi when the engine wants a 26 mm venturi, is just as ridiculous.

 

Check the third and fourth lines in my signature block.

 

EDIT: and to the OP, I have sold hundreds of these carburetors in the last 50 years, so yes, I do have experience with them. The key is to determine the TOTAL NEEDS of the customer, not just the lowest price! Those carbs do NOT work well on cars here in the Missouri Ozarks.

 

Jon.

Edited by carbking (see edit history)
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9 hours ago, oldford said:

From you comments, I obviously don't know that my car runs fine. I do know, after nearly 50 years in this hobby, and countless numbers of cars that I have owned, that my cars move along the road as they should without overheating, flooding, vapor lock, timing knock, etc. While I don't have nearly the experience or the knowledge that you possess, I have enough knowledge to keep me out of trouble, which is all I'm looking for. I must say that your arrogance flows from your keyboard in a manner I have not seen in a long time.

 

Frank


So if I know what I’m talking about makes me arrogant? Never said I was perfect , and don’t pretend to be. Bolting  on a carburetor and thinking your car runs correct is a poor excuse of a repair. Stoichometry is the correct term for making any fuel metering device to make a car perform as intended. Everything else is just short cuts and guess work. I don’t do half ass work.......on a Model T, or a Model J. Without an ignition scope, five gas tester, and a dynamometer.......it’s just half assed bolt on cheap fix. Take a chance to melt a piston or burn valves. It’s fine if you wanna run your car that way.  So you know what your exhaust gas temperature is , your fuel mixture is, and that you’re getting complete combustion. And you know that because you drove the car. To each his own. I fix cars correctly, and don’t make excuses. We pursue perfection with the hope of achieving excellence. 

 

 

Edited by edinmass (see edit history)
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Let's play nice.  A lot of good points here.  There are experts who have the knowledge and equipment to fine tune their vehicles to the nth degree.  I admire and am envious of those that possess that ability.  Some of us have to make do with what we got and tune by ear, by use of simple tools and by trial and error.  It sometimes is enough.  However, it has never been enough with me with Johnson carbs which came on my make of choice.  I missed the lessons on making those carbs perform flawlessly, instead they usually performed flawed! :) 

 

Jon, glad you have hung in here over the years.  One of the sad things on this forum is that many true experts like Jon, Ed and others have walked away and we have lost their knowledge and help.  Many of us appreciate hearing from you

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Steve......all good here on my end. No complaints. No worries. I just like helping people make good decisions. Bolting on a carb because it fits isn’t a good decision. Lots of bad things can and do happen. The world of internet blogs, short text messages, and grammar can make some people take things the wrong way......I’m not interested in upsetting people. I am interested in explaining how to correctly service pre war cars. All is good in the world. Hope you had a Happy Thanksgiving, the latest AACA magazine showed up today. It was the highlight of my day. The new building is fabulous, and the club and the members owe you a debt of gratitude for your accomplishment. The new club headquarters is an example of excellence..........something we see very seldom anymore in this country. You sir are a first class act. Bravo! And THANK YOU! 

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Steve - thank you. I did walk away for a month or so a few years ago, but a "forum friend" talked me back.

 

Us old geezers (Ed, by contrast, is a young whippersnapper ;) ) need to share our accumulated knowledge (or lack thereof) with those who will be old geezers in a few decades.

 

One thing many fail to understand is that sarcasm or irony may be difficult to recognize in print. Someone can get hurt feelings when there was no intent to hurt feelings, and strike back.

 

As to your Johnson experiences:

 

3 or 4 decades ago (long before the internet) a gentleman who specializes in Packards wanted to reproduce the Johnsons used by Packard for a few months in 1929 (ONLY). As we had spoken at Hershey, he knew I had several Johnson Packard parts carburetors. He owned various shops in the orient, and could have new castings done from better metal. We had several conversations via telephone. As he was a friend, and a good customer, plus the fact the Johnsons I had could never be made to function (Packard found in 1929 they didn't function after only a few months and recalled them!), I told him to expect a package via UPS. I packaged 3 or 4 Johnsons, along with an unopened bottle of Bayer, and sent them to him. I really think he appreciated my concern for his mental health about trying to make the Johnsons function and had sent him the Bayer! ;)  He called the day after receiving the package, and we had another long conversation.

 

The cars are the glue that keeps us together, but the friendships we make are probably much more important in the long run.

 

Jon.

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Back to the OP's original question:

 

Since the ad you posted has a Zenith carburetor number, it is quite easy to look up. This carburetor will work well on two models of Yale fork lifts!!! Probably very little else. It is not adjustable like the more expensive Zenith universal (but still cheap) carburetors.

 

There are no cars or trucks (road vehicles) for which I would personally sell this carburetor, at any price.

 

Jon.

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Jon, Amazon reviews state it works great on a 1926 2 Ton Caterpillar tractor......if you make an adaptor plate! Drive it like you stole it........at 2mph wide open throttle. 
 

The above statement is true.........👊

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Many years ago I successfully adapted two "universal" Zeniths to replace the Detroit Lubricator carbs on my 32 Cadillac V-12. It was a long and time consuming job involving custom linkage and fuel line mods but before I did so I consulted CarbKing and others to be sure the Zeniths would be compatible. In the end they worked quite well but were a substantial deviation from "stock". Good luck. 

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Don, that's not a Zenith, it clearly has Bendix cast into it!🤣

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Replying to Carbking, that image is just one I snapped from a choice of many as I have no idea which one would be best.

Some really good responses show how many enthusiasts have gone this path.

Now I'm thinking that if an very old car came with a certain carb... Surely it was at some stage it was running properly with said carb.

Seeing that my Tillotson JR 4 looks in good nick, I might source a carb kit with gasket and needle and seat.

Cheers

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1 hour ago, Tonz said:

Replying to Carbking, that image is just one I snapped from a choice of many as I have no idea which one would be best.

Some really good responses show how many enthusiasts have gone this path.

Now I'm thinking that if an very old car came with a certain carb... Surely it was at some stage it was running properly with said carb.

Seeing that my Tillotson JR 4 looks in good nick, I might source a carb kit with gasket and needle and seat.

Cheers

 

For those that totally disregard my advice on using the Tillotson, we do fabricate a carburetor rebuilding kit. Part number CS-1796. I do not recommend using the carb.

 

Jon.

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I was adding levity, as I do not see the Zenith name on my laptop picture. Too grainy for fine detail..

 

You did an excellent job installing those and getting the linkages operable.👍

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  • 2 weeks later...

I will second the recommendation from 29Sixty. I put a new Zenith model 68 on my 30 Essex and it works very well. I ran across the information at the Durant club website ( not a member) while searching for information, and decided on the 68 as my engine is 161ci. Used the 14544 tag number. I could never get the original marvel carburetor to stop flooding, then I tried an Allstate Model A carburetor which I admit was for a bigger engine. So far so good.

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We have been selling the Zenith universal carburetors for about 45 years. We are a Zenith distributor.

 

A couple of things we have learned:

 

First, the models 68 and 267 are TYPES of carburetors. Each of these come with SEVERAL DIFFERENT internal venturii sizes. For proper results, one MUST match the internal venturi to the air requirements of the engine. Simply ordering by 68 or 267 is a recipe for disaster!

 

Second, these are Zenith's INEXPENSIVE models. To sell for less than the more expensive models, there is a reason. These carburetors do NOT have power circuits. The power circuit augments the main circuit for wide open throttle operation. These work well in relatively flat terrain (i.e. southern Illinois, where one can see a mole-hill at 40 miles away). They do NOT work well in hilly terrain, such as the Missouri Ozarks where I live.

 

I have a wee bit of experience, as I have sold more than 1000 of these things in the last 45 years.

 

And yes, if one lives in a relatively flat terrain, and does one's homework to pick the correct unit by identification number (not the type), they do work well.

 

One also has to modify the carburetors for the fuel delivery system being used. These are designed for fuel pumps producing about 3 psi. If placed on gravity feed systems, they need to be disassembled, and an appropriate fuel valve installed.

 

EDIT: Unfortunately, the 14275 downdraft is no longer available. This, and its big brother, 14280 were exceptionally useful. All other numbers on the chart are current production units.

 

Jon.

Edited by carbking (see edit history)
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Jon, the issue is one guy who lives in the flatlands places it on on a car.....and he THINKS his car runs well. It doesn't, it's just that it ran so shitty for years that the new incorrect carburator is an improvement over the POS they had on it for forty years. Fact is, less than five percent of pre 1942 cars are running and performing at 100 percent. Most are usually around 75 percent at best.  Too many shady tree mechanics are certain of their skills........when actually they have no skill. For a car to run correctly..........as you know, you need a perfect ignition system, a perfect fuel delivery system, and a good mechanical system......the three are almost never present in the same engine........I could go on for hours, and I'm sure you could go on for weeks........my new carburator is doing the exact same thing as the old one held together with JB Weld........... I just got a car in that had 12k worth of work done on it, and the hole in the carburator was fixed correctly.......with J B Weld..........literally true, and just in the last 60 days.

Edited by edinmass (see edit history)
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ED - of course you are correct, however:

 

Sometimes it is necessary for "good enough".

 

Maybe an individual simply wants to drive the car in the 4th of July parade, or take his wife on a drive through the countryside.

 

If the carb doesn't leak (safety issue), is not going to explode because of the early pot metal (serious safety issue), and will run the car without issue for these short drives; then maybe it is good enough for many folks. It doesn't have to produce maximum horsepower, as long as there is sufficient so the car can be driven safely.  If they plan to enter the "Great American Race" I won't sell them the cheap carburetor.

 

As an example: the Durants mentioned in this thread used zinc alloy (pot metal) Tillotson carburetors. One can argue the merits of using a Tillotson on any engine, but I won't in this thread. But I have not seen a usable pot metal anything from the 1927~1929 period. And we know the popular Stromberg U-2 castings have been professionally remade, as has the Zenith 105DC. So the Durant owner has three choices: (1) he/she locates the correct Tillotson, carefully disassembles, mills everything until plumb, epoxies all of the dozens of cracks; and then takes the castings to a foundry that specializes in lost wax casting (showing my age here, new technology may exist), has new castings fabricated, has the castings machined, and then transfers all the parts. Costs??? Probably more than the car will bring at one of the television auctions. (2) find a replacement unit that will allow he/she to enjoy the vehicle, or (3) park it, permanently.

 

Each individual must make their own decision. Is the universal carb going to work perfectly.....NO; but is it going to work well enough for enjoyment without breaking the budget?

 

When the original is simply not feasible (impossible to find, not economical to repair, etc.) I try to suggest a carb that was engineered specifically for the application rather than the universal, but some folks look at the bottom line, which is OK, if the less expensive units will suit THEIR needs.

 

Perfection is great, but sometimes perfection is more costly than may be necessary.

 

And as you can probably guess, my projects tend to go a "wee" bit over budget!

 

Jon

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One of the universals I remember quite well.

 

This occurred at the POCI convention in Gettysburg in 1980. We were set up in the swap meet, and a gentleman of maybe 60 dropped by to look at our carburetors. He was the shop foreman for the local Pontiac agency, and the owner had a 1929 Oakland with a Marvel which he described as less than marvelous (in fact his comments would have made a sailor blush).

 

I showed him the Zenith, explained the adjustments, and we talked about what was planned for the car (parade advertising, customer rides, etc.).

 

I priced him one, and he said he might be back tomorrow, he had to check with the owner BCP (before cell phones :P ).

 

Well, he was back the next day and purchased one.

 

About two weeks later, I got a call. He identified himself. Once the shop had some space, they had rolled out the Oakland, and while every mechanic in the dealership looked on (they had all tried to make the Marvel function) he personally filled the carb with gasoline, and installed the carb. While he was under the hood with a fire estinguisher (remember, they were used to the Marvel), another mechanic cranked the engine. It started on the first revolution, and the resulting cheer was audible 3 blocks from the dealership (his words).

 

Quote Hannible Smith "I love it when a plan comes together" End quote.

 

Jon.

Edited by carbking (see edit history)
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This question if for car king,I have a 1931 devaux it originally had a tillotson j2a carburetor,sometime in the 50 s it was changed to the replacement jr2a which I understand is the direct replacement,is this carburetor in your opinion a better barb or should I go to the zenith, thank you.   Dave

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Dave - the J2A was designed as an original carb; the JR2A, even though the type is so similar, was one of a family of universal replacement carbs (the "R" meant replacement). Not knowing the construction of the J2A, I would think that, if the castings are usable, it would be more suited to the application.

 

If one can find a Zenith with the correct internal venturi, that will physically fit on the Devaux, the Zenith is better than either of the Tillotsons.

 

Jon

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On 11/30/2021 at 9:53 AM, TexRiv_63 said:

Many years ago I successfully adapted two "universal" Zeniths to replace the Detroit Lubricator carbs on my 32 Cadillac V-12.

Beautiful work. 

Eliminating the Detroit Lubricators I guess was a good move and it doesnt seem to garner negative feedback from the experts. 

 

How do the experts feel about changing a Cadillac Johnson for something else? 

Especially when they have stated that a Johnson runs about as good a pouring in fuel from an old boot. . . .

But maybe there is nothing else that will fit/work beyond engineering a downdraft. :-( 

Edited by m-mman (see edit history)
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I'm one of the guys who always says not to go changing the shitty carburetors on any early Cadillac. You can make the run well........it's just an asinine amount of time, money, blood, sweat, and tears. There isn't anything much worse than a Cadillac Johnson unit. Get them dialed in, and they are ok, except for the constant fuel leaking out over time. On a CCCA tour I was passing a 1941 Packard 160 with my 1931 Cadillac 355 V-8 on the hills....at the next stop, the Packard guy came over to me, and said......I'm opening you hood, I have one of these, and there is no way you're running a stock carb and fuel system. He was wrong...........it just took about 75 times pulling the carb to get it set up correctly. By the time I figured it out........I decided to sell all my Cadillacs and drive Pierce Arrow's.........so I should say thank you to them for building suck a pile of junk.....it's what turned me into a Pierce guy. 35 years later, and now I have to deal with them at work during company time...........One of the cars in our collection took me about 80 hours to get dialed in........just the fuel system........and it was a 100 point car. Once set up correctly, the Cadillac Johnson will stay where it's put.....and then become trouble free.........getting there is like climbing Everest. 

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Comparing the Detroit carbs to the Johnson carbs is like comparing apples and lemons; two totally different reasons to consider replacement.

 

Considering first the Johnson (the lemon :P ):

 

Like Ed, I COULD make one function, but I wouldn't trust it. And if I cannot trust it, I will not do it. Reliability (in this case, read as "safety") is the most important component on a carburetor for a car being driven. I have posted this before, but I am quite paranoid on this subject, as I lost a good friend decades ago to an engine fire started by a faulty carburetor. No, I did not do the carb, so it is not a guilt trip, but nevertheless, I lost a friend. He wasn't as spry at his age as he had been, and simply could not get out of the car. It was a Ford Model A, which illustrates issues can happen to anything. Reliability is the reason for replacing the Johnson. So maybe take some of my posts about reliability with a grain of salt ;)

 

There are two reasons for replacing the Detroit carbs on the V-12: (1) one cannot be found at any price, and (2) cost of repair or cost of the Detroit if you did not have one. For a professionally repaired carb (if you can find a professional that still does them) the carb should easily deliver 15~25k trouble-free miles. Reliability is not an issue. I would rank the Detroits right along with the best Strombergs and best Zeniths for quality and reliability.

 

I have wondered about the possibility of replacing the mid-20's and newer Cadillac V-8 Johnsons with the Cadillac V-8 1934 or 1935 Detroits, but as I don't own one of the cars, have never tried to make it happen. The V-8 Caddy Detroits are much more common and less expensive than other Detroits, and there seems to be no demand (they are so reliable no one needs one???). We have converted several into Super 8 Packard carburetors.

 

Jon

Edited by carbking (see edit history)
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14 minutes ago, carbking said:

Like Ed, I COULD make one function, but I wouldn't trust it. And if I cannot trust it, I will not do it.

And without having access to specific testing equipment, the decades of experience to understand how to interpret the findings, and unlimited time to perform the repairs . . . this is why most hobbyists will "just bolt on a universal carb and drive it around" . . . .  It may not be good - but it is good enough for me. 

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Some interesting discussions and thanks to Carb King and Edinmass for your contributions. It definitely is food for thought.

 We had an old guy here years ago, who rebuilt or modified carbs for all types of cars. He started as an apprentice back around 1910 and opened his own business in 1932, mainly specializing in carbs and auto electrics. I spent an afternoon with him having tea and left a terraplane carb with him, that I could not get a stubborn jet to come out. He somehow removed it and made a new one. In one of his discussions he said there was a formula for working out the size of venturi needed etc, depending on the size of the motor, but he would not tell me what that formula was, and unfortunately that info and a lot of his knowledge went with him to the grave. Do either of you guys know what formula to use when determining the venturi size needed?

  Looking at some of the other posts above, there is one from Articifer Tom about his 1931 Dodge, the picture shows what appears to be a 4 cylinder Plymouth engine, a bit confusing.

 Also, getting back to the original posting from Tonz using a Tillotson carb on his 1926 Chrysler. Tonz you failed to mention what model of Chrysler you are working on, is it a four or six cylinder car?? and what model?

 I had a 1928 Model 52 that came to me in a thousand pieces, the original Carter carb ( with disintegrated diecast bits) had been replaced with a Model A ford Zenith carb and after a complete rebuild of the whole car, I ran it for several decades with the Model A carb, using the same rod type choke and adjustable jet. It performed very well over all types of terrain and I never had any problems with it, but having read the above discussion, I cannot confirm it was strictly right. The Model A motor is a bigger displacement than the Chrysler and I have no idea if the venturi sizes were the same.

 On another side of things, I have read up on alcohol blended gas and it has opened my eyes to a few things. When the old cars were built the gas was not such a high octane as we have today, even the regular gas is a higher octane than was available back in the 20's. Some said that the low compression motors, do not burn all the higher octane gas in the combustion chamber, so when exhaust valves open the still burning fuel is pushed out into the exhaust manifold, causing the motor to run hot. At the time I owned my model 52, I noticed on a long run of say 100 miles the exhaust manifold would get red hot, I never knew about this octane thing 25 years ago and wonder if adding a percentage of diesel or paraffin to the gas (as suggested) would have solved this problem.

 I look forward to others opinions on this subject.

 Best regards to all of you and wishing everyone on the forum a merry, blessed and peaceful Christmas and everything of the best for next year.

 Viv.

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