Dual Carbs

[Drifter99]

Any body running George Ashe dual carbs? I am interested in the performance or advantage of them or how it affects the gas mileage. I would suppose you would need to open the exhaust also.They look cool!! Thanks Robin

[Jim Shepard]

While someone from the car side can answer your question, I'd be real surprised if anyone is running dual carbs on one of our trucks.  I've never heard of anyone doing it. I looked at doing it awhile back (even had the offy intake) but the linkage issue was too much trouble. The dual setups were made for the cars and there is a significant difference in the way the linkage works. I decided to go with the factory 2bb setup used on the mid-fifties cars. Even at that, there are some linkage mods I will need to make...  If anyone has gone to duals on a truck please post a few photos - I'd love to see how you handled the linkage.

[Young Ed]

While someone from the car side can answer your question, I'd be real surprised if anyone is running dual carbs on one of our trucks.  I've never heard of anyone doing it. I looked at doing it awhile back (even had the offy intake) but the linkage issue was too much trouble. The dual setups were made for the cars and there is a significant difference in the way the linkage works. I decided to go with the factory 2bb setup used on the mid-fifties cars. Even at that, there are some linkage mods I will need to make...  If anyone has gone to duals on a truck please post a few photos - I'd love to see how you handled the linkage.

 

I've got both a fenton dual intake and a mopar 2bbl to use for my 40 plymouth pickup. Like you I've been trying to come up with an idea for that. So far I'm leaning towards using an early 50s car pedal with a throttle cable like Blueskies did.

[Drifter99]

Linkage is always the thorn in the heel. There's been a lot of talk of heating of the manifold with two carbs that they frost up. I guess your right not big on our trucks.

[55 Fargo]

Hmm, just brought up this idea on the car side, discussing a 2bbl carb with adaptor on 1 bl stock intake. on my 55, trying to run duals, would no doubt have same issues.

Would splitting the exhaust, and running a 2bbl carb be a better approach? Would this give me some added HP boost that would be a noticeable difference?

[55 Fargo]

Anyone ever use the Rusty Hope bolt on exhaust outlet? If you have can you post some comments and pics...

[Dave72dt]

Until someone does it and actually tests it with before and after runs on a dyno, its just guessing which will do better and how much of an increase might be found with either. My personal opinion would be an intake that did not require an adapter would work better than one that did. Splitting the exhaust may or may not be detrimental to the scavenging effect of an exhaust as far as assisting the flow of the fuel mixture into the chambers or the distribution of the mixture within the intake manifold itself possibly causing a lean mixture in some chambers and rich in others. Linkage can be made to work regardless of orientation of the carb(s). The trick is making it look like it belongs there.

[Don Coatney]

Until someone does it and actually tests it with before and after runs on a dyno, its just guessing which will do better and how much of an increase might be found with either.

Dave is 100% correct. Proof is in the dyno. But the dyno will not measure the unique sound of a split exhaust nor the coolness of multiple carburetors.

[55 Fargo]

Dave is 100% correct. Proof is in the dyno. But the dyno will not measure the unique sound of a split exhaust nor the coolness of multiple carburetors.

Absolutely, but the throttle response must be evident. I would suspect shaving the head, would help with a little boost in this equation too..

[Plymouthy Adams]

dual carbs meet a certain level of cool...but to be effective the entire package must be considered..upping carburation is only needed if you are making the engine a deeper breather..that will be the direct result of a better cam with greater duration and higher lift...breathe deep you will no need to ability  to exhaust these gases.  Hotter ignition will come into play..change the cam profile and you will need often to address rear ratio for keeping the engine in the correct band of operation as determined by the cam but as most of these are 3.9-4.1 this may well be the only area not needing addressed....shaving the head to up CR would be necessary to take full advantage of all the work being done...now, all this sounds great but there are trade offs on smooth idle, torque curve change and such that affect the very daily drive qualities of the factory engineered smooth flattie....I assure you the engineers of the day could well have produced the very combination you are seeking but their goal was best power and economy and performance for the money and do this in  a manner to ensure a very long life of the power plant..just do consider these trade off as you proceed forward with your mods...

[55 Fargo]

dual carbs meet a certain level of cool...but to be effective the entire package must be considered..upping carburation is only needed if you are making the engine a deeper breather..that will be the direct result of a better cam with greater duration and higher lift...breathe deep you will no need to ability  to exhaust these gases.  Hotter ignition will come into play..change the cam profile and you will need often to address rear ratio for keeping the engine in the correct band of operation as determined by the cam but as most of these are 3.9-4.1 this may well be the only area not needing addressed....shaving the head to up CR would be necessary to take full advantage of all the work being done...now, all this sounds great but there are trade offs on smooth idle, torque curve change and such that affect the very daily drive qualities of the factory engineered smooth flattie....I assure you the engineers of the day could well have produced the very combination you are seeking but their goal was best power and economy and performance for the money and do this in  a manner to ensure a very long life of the power plant..just do consider these trade off as you proceed forward with your mods...

hey Tim, sometimes if it ain't broke don't fix it" rings true. I do like what others have done, but there are all things to consider, thanx for your input.

A side note, I have a set of manifolds sitting on my bench, intake is separated from the exhaust, the heat riser is in good working order. But the exhaust manifold is got a break around 1 of the 2 bolt/stud areas on the very center of the exhaust manifold, would something like this be worthy of a repair, hence allowing me to use this set-up as per stock once again?

I could post a pic of damage it anyone likes to see it.

[Plymouthy Adams]

Fred....you will have to carry the unit to a welder experienced in manifold repair...the ability of the shop is the very "guarantee" that it can be done...cast iron work is a process.....drill and prep cracks and such. preheat...do a expert weld process..then cool the cast iron over a period of time slowly reducing the heat.

 

I do not think many folks here could say yes to your question with our without picutres as they do not know the expertise of the shop/individual doing the work...but to say the probabilities of success are higher with experience..then yes..

[55 Fargo]

Thanx Tim, to OP, did not mean to take this thread into another direction, apologize for that. Here is a pic of the manifold.

[41/53dodges]

That manifold looks decent enough, but actually getting in there to repair would be pretty difficult! You may be better off to scrounge for a new manifold, I know I keep a spare set around, good for replacing or tinkering!

[austinsailor]

Guess I don't know what to look for, I don't see the crack. But, in addition to the welding you'll probably have to have the surface cut flat again. It'll probably warp when it's welded. Adding the expense of that, I'd guess you could find another manifold cheaper. It's not so rare as to be worth putting a lot of money into, is it?

[55 Fargo]

Guess I don't know what to look for, I don't see the crack. But, in addition to the welding you'll probably have to have the surface cut flat again. It'll probably warp when it's welded. Adding the expense of that, I'd guess you could find another manifold cheaper. It's not so rare as to be worth putting a lot of money into, is it?

True enough, the hole is on the right side bolt hole through center are of manifold..

[HanksB3B]

I'm expecting the UPS man to drop off my VPW maniforl kit with the special types of washers and nuts.  I guess since this thread got semi-pirated now would be a good time to mention it. My nuts were all messed up and that went for the washers too. I found three of the brass washers where they didn't belong and one of them was cracked. Steve at Vintage Power Wagons told me the nuts are also supposed to be brass, something I had never heard let alone seen on my truck. My manifolds are not cracked and are in good shape even though they were not installed correctly. I attribute this to the fact I live in Southern California where at worst my cold engine is going from 50 deg to 160-180 at full operating temperature.  Starting an engine in sub-zero conditions has got to be extreme if the outer temperture of the exhaust manifold is -20 deg and the fire is 170 deg inside the cast iron manifold.  What I'm trying to say is as a truck owner up North I think it's very important that the factory setup be followed. Parts are getting much harder to find these days. (like that darn spring of your heat riser I know they are out there but I don't want to buy the whole kit)

 

Hank   

Edited January 3, 2014 by HanksB3B

[55 Fargo]

I'm expecting the UPS man to drop off my VPW maniforl kit with the special types of washers and nuts.  I guess since this thread got semi-pirated now would be a good time to mention it. My nuts were all messed up and that went for the washers too. I found three of the brass washers where they didn't belong and one of them was cracked. Steve at Vintage Power Wagons told me the nuts are also supposed to be brass, something I had never heard let alone seen on my truck. My manifolds are not cracked and are in good shape even though they were not installed correctly. I attribute this to the fact I live in Southern California where at worst my cold engine is going from 50 deg to 160-180 at full operating temperature.  Starting an engine in sub-zero conditions has got to be extreme if the outer temperture of the exhaust manifold is -20 deg and the fire is 170 deg inside the cast iron manifold.  What I'm trying to say is as a truck owner up North I think it's very important that the factory setup be followed. Parts are getting much harder to find these days. (like that darn spring of your heat riser I know they are out there but I don't want to buy the whole kit)

 

Hank   

Carb icing is more common at temps right around 32f, most people run there vintage vehicles only in warmer weather up here, temps above 50f. So Heatrisers are not a big deal either...

Only crazy frosties like me , drove there old trucks today in 5 below weather........LOL

[HanksB3B]

Carb icing is more common at temps right around 32f, most people run there vintage vehicles only in warmer weather up here, temps above 50f. So Heatrisers are not a big deal either...

Only crazy frosties like me , drove there old trucks today in 5 below weather........LOL

 

 Brings back fond memories of driving my 47 Willys thru the snowy backroads of old Vermont windshield down...

 

Hank 

[Drifter99]

Fargos,, keep truck n brother -5 !!

[Don Coatney]

Carb icing is more common at temps right around 32f,

 

I don't believe that is true. Carburetor icing is internal and occurs when there is a lot of moisture in the gas and or the relative humidity is very high irrelevant of ambient temperature. When the fuel charge passes through the carburetor venturi it expands due to intake manifold vacuum thus rapidly dropping the temperature same way as any mechanical refrigeration device works.

[55 Fargo]

I don't believe that is true. Carburetor icing is internal and occurs when there is a lot of moisture in the gas and or the relative humidity is very high irrelevant of ambient temperature. When the fuel charge passes through the carburetor venturi it expands due to intake manifold vacuum thus rapidly dropping the temperature same way as any mechanical refrigeration device works.

Yes, that's true, but I have only experienced it when those ambient temps were near freezing point, very high humidity, either rain/sleet/snow. I have never experienced this in cold dry weather, that was my point. For example, yesterday it was 5 below, relative humidity 80% barometric pressure dropping, today it's 18f, 88% humidity, snowing would not happen today either. But if temp rises to 25 f, humidity rose to 98% with wet snow and rain, icing sure could happen.

I used to have a 79 ford with an inline 6, that car liked to have icing conditions in carb, with high humidity and temps closer to freezing..

[John-T-53]

I'm running dual 1bbl's on my truck and they have been working working great. I got the George Asche setup with manifold supplied by him as well. Linkage is very easy - just hook it up to the stock bell crank on the manifold. I'll try to post some pics this weekend.

[Drifter99]

John, good to hear any chance you running his the cam he sells? FYI waiting on my ring kit and found a shop to drill the bell housing. Did you replace the bushing in the bell housing on the end of the throw out shalf if so where did you find it?

[wallytoo]

Carburetor icing is internal

it is? what's the frosty-looking substance on the exterior of mine?

i believe you are correct about the relative humidity, ie, more likely to ice-up with high r-h. and it occurs when the ambient temp is above freezing, too (i know you know that).