Don't understand cams

[FrostyMopar]

I'm just going to ignore the one beating his chest.

Picking the appropriate duration and lobe separation is how you get valve events. (with a certain amount of advance, but that doesn't have to be ground in)

Let me try to put it in a more simplistic way

A cam manufacturer will want every detail you have available for your engine/application.

Bore, Stroke, Rod length, Compression ratio, Cylinder head flow CFM, Valve sizes, converter flash or stall RPM, transmission, differential gears, tire diameter etc etc

They will want to know what the vehicle/engine is going to be used for. Street, Performance street, Street/strip, Circle track, Drag race, Mud racing etc etc.

When all these factors are known, they will already have an idea in their head of roughly what kind of camshaft you need. They will refer to their experience with relatively similar combinations to yours which were successful.

Firstly, a camshaft has lobes.

Lobes are listed in a cam manufacturer's master catalog.

The lobes operate the valves.

"Duration" of a lobe is how long in crank degrees the valve is moved by the camshaft.
"lift" is how far the valve is moved at the lobe's highest point.

Duration has a 100% predictable effect, more duration means it moves the power into the higher RPM range.

200 degrees is a lower rpm lobe which won't make as much power at high rpm.
260 degrees is a higher rpm lobe which won't make as much power at low rpm.

Lift is mostly a function of a cylinder head's capacity to flow air. The higher the lift the better the performance, however you can only get so much lift with a given duration because of physical limitations. Especially with a flat tappet camshaft.

The relative lift to duration is what is known as "Ramp rate". Higher ramp rating is great for performance, but can make an engine become noisy. ramp rating is limited by reliability factors.

Lobes will be listed in a catalogue in a series, first categorized by type.

Hydraulic flat tappet.
Solid flat tappet.
Hydraulic roller.
Solid roller.

Each type will have a few variations.

Some lobes are high ramp rating. (racing only)

Some are low ramp rating (factory replacement)

Some are designed specifically for exhaust only.

Some are designed for classes with a maximum lift rule in racing. these are like normal racing lobes with all parts of the lobe which exceeds a specified lift value machined off.

Some are designed with low ratio rocker arms

Some are designed with high ratio rocker arms

Some are designed for valvetrain stability at 10,000 RPM.

Some are designed for towing.

Picking the correct lobes is SUPER IMPORTANT.

If you have basic comphrehension skills, you should pretty obviously see why Picking lobes is the correct place to begin when a professional designs a custom camshaft for a customer.


However when selecting the lobes, you need to take into consideration where the Intake lobes are going to be placed in relation to the exhaust, because this effects the cam's performance dramatically.

The way we select the location of the lobes, is with "lobe separation angle"

Lobe separation angle also has a 100% predictable effect, just like duration. I've already been through them in this thread. but here they are again anyhow.

Now every motor is different. So the correct cam for a 225ci slant six won't be the same for a 440.

The cam manufacturers have experience and first hand knowledge in what works with particular applications. But for example a 350 chev, 351 ford, and 360 mopar with the same compression ratio and cylinder head flow are going to need similar cams if they have a common purpose/rpm range.

This experience and knowledge is less about being an award winning mathematician and more about experience which makes them aware of What lobes to select and where to put them.

Even a very good professional cam guru will probably look at a bunch of valve event timing figures and then instantly perform the maths to convert it to Duration and Lobe separation to figure out what the heck the cam is actually good for.

Measurements like Valve timing events are something which occurs as a result of picking everything else. Much like overlap

You wouldn't go to a cam manufacturer and say "I want a camshaft with 22 degrees valve overlap".

I'm sure they would be polite if you did, but it's not helpful in determining the correct camshaft.

Valve timing events are similar, but to a lesser degree.

Regardless. The best advice you can get WILL ALWAYS come from a tech at a cam manufacturer, not an internet forum.

 

[yellow rose]

I'm just going to ignore the one beating his chest.

Picking the appropriate duration and lobe separation is how you get valve events. (with a certain amount of advance, but that doesn't have to be ground in)

Let me try to put it in a more simplistic way

A cam manufacturer will want every detail you have available for your engine/application.

Bore, Stroke, Rod length, Compression ratio, Cylinder head flow CFM, Valve sizes, converter flash or stall RPM, transmission, differential gears, tire diameter etc etc

They will want to know what the vehicle/engine is going to be used for. Street, Performance street, Street/strip, Circle track, Drag race, Mud racing etc etc.

When all these factors are known, they will already have an idea in their head of roughly what kind of camshaft you need. They will refer to their experience with relatively similar combinations to yours which were successful.

Firstly, a camshaft has lobes.

Lobes are listed in a cam manufacturer's master catalog.

The lobes operate the valves.

"Duration" of a lobe is how long in crank degrees the valve is moved by the camshaft.
"lift" is how far the valve is moved at the lobe's highest point.

Duration has a 100% predictable effect, more duration means it moves the power into the higher RPM range.

200 degrees is a lower rpm lobe which won't make as much power at high rpm.
260 degrees is a higher rpm lobe which won't make as much power at low rpm.

View attachment 1714987668

Lift is mostly a function of a cylinder head's capacity to flow air. The higher the lift the better the performance, however you can only get so much lift with a given duration because of physical limitations. Especially with a flat tappet camshaft.

The relative lift to duration is what is known as "Ramp rate". Higher ramp rating is great for performance, but can make an engine become noisy. ramp rating is limited by reliability factors.

Lobes will be listed in a catalogue in a series, first categorized by type.

Hydraulic flat tappet.
Solid flat tappet.
Hydraulic roller.
Solid roller.

Each type will have a few variations.

Some lobes are high ramp rating. (racing only)

Some are low ramp rating (factory replacement)

Some are designed specifically for exhaust only.

Some are designed for classes with a maximum lift rule in racing. these are like normal racing lobes with all parts of the lobe which exceeds a specified lift value machined off.

Some are designed with low ratio rocker arms

Some are designed with high ratio rocker arms

Some are designed for valvetrain stability at 10,000 RPM.

Some are designed for towing.

Picking the correct lobes is SUPER IMPORTANT.

If you have basic comphrehension skills, you should pretty obviously see why Picking lobes is the correct place to begin when a professional designs a custom camshaft for a customer.


However when selecting the lobes, you need to take into consideration where the Intake lobes are going to be placed in relation to the exhaust, because this effects the cam's performance dramatically.

The way we select the location of the lobes, is with "lobe separation angle"

Lobe separation angle also has a 100% predictable effect, just like duration. I've already been through them in this thread. but here they are again anyhow.

View attachment 1714987669

Now every motor is different. So the correct cam for a 225ci slant six won't be the same for a 440.

The cam manufacturers have experience and first hand knowledge in what works with particular applications. But for example a 350 chev, 351 ford, and 360 mopar with the same compression ratio and cylinder head flow are going to need similar cams if they have a common purpose/rpm range.

This experience and knowledge is less about being an award winning mathematician and more about experience which makes them aware of What lobes to select and where to put them.

Even a very good professional cam guru will probably look at a bunch of valve event timing figures and then instantly perform the maths to convert it to Duration and Lobe separation to figure out what the heck the cam is actually good for.

Measurements like Valve timing events are something which occurs as a result of picking everything else. Much like overlap

You wouldn't go to a cam manufacturer and say "I want a camshaft with 22 degrees valve overlap".

I'm sure they would be polite if you did, but it's not helpful in determining the correct camshaft.

Valve timing events are similar, but to a lesser degree.

Regardless. The best advice you can get WILL ALWAYS come from a tech at a cam manufacturer, not an internet forum.

 

[yellow rose]

You have an *** backward way to design and pick a lobe.


Maybe you should read what I wrote, many times until you understand. I'd bet you big money to prove if we called the same company with the same specs, my cam would make more HP all over.

I know my system works. You, you just print much words and hope that you are heard.

Better luck next time.

 

[Cudafever]

LOL and here i thought i had killed this thread!!!!!!

 

[Johnny Dart]

To the original poster. Mild 340...Comp XE268. Insert key, light em up.
That was easy.

 

[roccodart440]

I didn't ask the customer if I could do it. I did it. I don't ask the customer. Just pay money and shut up. If you don't like it, there's other shops out there.

This is bad business. If my engine builder ever took this stance I'd find a new one. Which is what you suggest.

I'd bet you big money to prove if we called the same company with the same specs, my cam would make more HP all over.

But in a street car that isn't the number one goal.

Very little of the level of detail he gets into is at all relevant on a 100% street engine where the budget is tight and the power levels are lower than 1.1hp/inch. Nobody building a street cruiser is spending to maximize high lift flow and reduce low lift. NOBODY.

While there is no doubt you understand cam technology, I can't get behind your mentality nor the logic. Reminds me of the last build I did. He wanted a "nasty, choppy, radical idle and 500hp" in a 100% street driven pickup truck. Well, he got exactly what he wanted. And...he hates it.

 

[yellow rose]

This is bad business. If my engine builder ever took this stance I'd find a new one. Which is what you suggest.



But in a street car that isn't the number one goal.




While there is no doubt you understand cam technology, I can't get behind your mentality nor the logic. Reminds me of the last build I did. He wanted a "nasty, choppy, radical idle and 500hp" in a 100% street driven pickup truck. Well, he got exactly what he wanted. And...he hates it.

Then I would have supported you, as the builder, to tell the customer to pack sand. I have. Let some other builder listen to a customer who is smarter than the builder listen to the customer *****.

Unless we had a working relationship, I would do what I wanted to do.

Do you own a flow bench? Dyno? Do you develop your own tooling for valve jobs and then test it (at least one of my cutters is in a catalog but it has very limited usage)? I can think of about 8 different cutters I designed, all with a purpose.

What I don't understand how you think it's ok to build an engine and not get all out of you can. Seems stupid to me. And that is what you are arguing. You think anything that makes more power MUST give up drivability, and that isn't true.

So the fact is, you may never understand it. Can't tell you how many customers heads I actually, with intent, reduced low lift flow, used the correct cam and picked up power and drivability. And they would have no idea if I would have shown them what I did.


That's why you pay. You are paying for KNOWLEGE and EXPERIENCE.


Again, I don't see how you can say making more power all over isn't the goal. If that's the case, you should build it dead stock. But even that can be improved on. So why pay and not get value?


Your "logic" is unreasonable and unfounded.

 

[318willrun]

My opinion is there are many good cam companies that have done the homework for you and many off the shelf cams have worked very well. And that includes 4x4's, street, strip, bracket cars, and very tame cruisers.
The companies have done a great job giving idle character, rpm ranges, and general applications for each cam including exhaust, converter, and gears.
Not to say one can't improve on a specific custom grind for a specific engine. But off the shelf cams will work just fine for most builds.

 

[T-N-T]

Does reducing low lift flow and increasing high lift flow go hand in hand if you are using an aggressive roller cam? I have a feeling that is one case where it does. A slow ramped flat tappet cam needs that low lift flow to match the ramp speed to get air moving I believe.

 

[Cudafever]

YR, you are someone that is pist off when HP is left on the table, and i love that!!!!!
But you need to be looking at competition class racing, like stock or super stock to afford that level performance. Have you seen the kind of power and rpm they can make out of a "stock" 360/1.88 valve eng make! WOW!!!!!!!!!!

roccodart440, His plans could be two rich for your blood as well but, but he can still sleep at night with a small chip and dust on the table But he can make it to your lever.

Now let's go down......hmm no let's get to the Op level. You want us to recommend a cam for you. If this thread and turn out the way you wanted it too. You would have got 2 0r 3 cams to choose from right. and that would be great, right! NO.......that's a MP cam and its out dated here's 2 or 3 cam from comp, because they're better! HEAL NO every cam i got from comp when bad, Buy this cam from lunati, there much better.....then..........Get the Voodoo Series cam as they have a much faster ramps bla bla bla and there 10 more cam companies that 10 more people will recommend.

Then the last but surely not the least. Call
"a" cam company and listen to their recommendations.
My personal opinion, THE right "of the shelf cam" was designed with a stock head in mind and will be vary close.

YR and roccodart440 I truly believe that both of you are 100% right............But then again i think i'm Right as well!

 

[moper]

I'm not picking a fight. It's called point it out facts. Do you have a problem with facts?
You have no idea what a machine shop does. I know when I did a valve job and I was selling the cam, I did a valve job to reduce reversion and reduce low lift flow. I didn't ask the customer if I could do it. I did it. I don't ask the customer. If you think you are smart enough, then you should do your valve job and do your own ****.
The last thing I want the customer to do is help me. Just pay money and shut up. If you don't like it, there's other shops out there.
If you knew how many custom cams I sold compared to shelf junk since 1999, you'd realize how stupid your statement is.

I love it - reference a reverence for facts and then make up a story to minimize me.
What did you do prior to '99? I was working in a performance automotive machine shop. Two, actually. The first one started in the 80s. I almost bought the second one in '05 but the required stipulations to the sellers were not met and my other career path was evolving to a better place anyway. I have a guide and seat machine in my garage with thousands of dollars of tooling. A close friend has an SF-600 in his. I never said you were wrong. I said you're presenting info that is totally irrelevant except to make yourself sound like a Mopar hero which is your M.O. I don't pay my mortgage building engines. The only vested interest I have is helping where I can. What's your interest here, because you haven't done anything in this post besides be a dick.

 

[yellow rose]

I love it - reference a reverence for facts and then make up a story to minimize me.
What did you do prior to '99? I was working in a performance automotive machine shop. Two, actually. The first one started in the 80s. I almost bought the second one in '05 but the required stipulations to the sellers were not met and my other career path was evolving to a better place anyway. I have a guide and seat machine in my garage with thousands of dollars of tooling. A close friend has an SF-600 in his. I never said you were wrong. I said you're presenting info that is totally irrelevant except to make yourself sound like a Mopar hero which is your M.O. I don't pay my mortgage building engines. The only vested interest I have is helping where I can. What's your interest here, because you haven't done anything in this post besides be a dick.

Geesus, you get butt hurt often?

I try to learn something every day. I just learned that some people won't learn.

Later dude.


BTW, why don't you find one thing I said was wrong and post it up. I'm willing to learn. I know guys doing this **** since the 60's and they still do their valve jobs with a stone, hone a cylinder like its 1975 and treat a dyno and flow bench like a red headed step child. Just because you've been doing something for years don't mean you do it right.

 

[FrostyMopar]

You have an *** backward way to design and pick a lobe.


Maybe you should read what I wrote, many times until you understand. I'd bet you big money to prove if we called the same company with the same specs, my cam would make more HP all over.

I know my system works. You, you just print much words and hope that you are heard.

Better luck next time.

I agree with you in that you are stressing that each valve timing event needs to be in the correct position, I just don't agree that trying to look at each one individually is a good starting point for designing a camshaft, since all valve timing events shares a function or functions (air in the intake, or air out the exhaust. compressing mixture) with at least one other valve timing event. They are HEAVILY influenced by each other, so why begin the design by looking at them individually when you don't have to?

To put that in simpler terms, the flow and pressure is influenced by more than one valve timing event throughout an engine's entire 720 degree cycle, so designing a camshaft "one valve event at a time" just seems like the long way around.

The specs of each valve timing event as measured in relation to TDC or BDC are important, nobody would deny that. But how are orientated in relation to each other is much more telling.

Having insight into how those valve timing events work IN UNISON is what really tells if a camshaft is going to be suitable for a customer's application. There's simply no getting around this fact.

That "unison" can be looked at with 100% predictability and 100% accuracy by looking at Duration, Lobe separation and advance since these figures indicate everything there is to know about the valve timing events and how they will work in relation to each other.

This is also helpful to camshaft manufacturers when actually creating the camshaft because they do this by copying entire lobes from a master, instead of "starts and finishes" of lobes.

Those lobes are oriented and machined as specified by the lobe separation angle.

I'm not saying your way won't work, i just think You're doing it the hard way.

Good luck with that, and try not to wear the buttons out on your calculator. ;)

 

[mpd12150]

Is this cam good to use in a 72- 340 with factory style rockers, lifters and push rods ?
Also, will this make my engine have a real lumpy idle ?
Sorry for a stupid question, but I've never understood camshaft, lifts and durations.
What would factory specs be for a 1972- 340 engine?View attachment 1714985708

I just completed the build for my 69 Dart GT. I built a stroked 408 and took the advice of a friend of mine when it came time to get the cam ordered. A good friend of mine who runs an Outlaw Class 10.90 time iron head stroked 408 gets his cam from a company named, Bullet Cams. They are a small company that custom grinds cams for YOUR specific application. If you go to their web page, www.bulletcams.com, then move your cursor over the contact tab, you will see a cam recommendation subtitle. Click that link and it will give you every single bit of information you will ever need to have them grind you the cam that you are looking for that will be specific to YOUR application. When using big box cam companies, they are mostly generalizations that will work ok with your application and generally speaking will be fine.

I took the time to fill out the form for Bullet Cams and spoke with TIm Langley from Bullet and they built me a cam for my application and I can tell you, I have never been happier. Bullet is a smaller company who can concentrate on quality control and provide you with the best product on the market. I am of course giving you my opinion and there are hundreds of individuals on this page who are absolutely amazing professionals who are always willing to help and do give kick *** advice and they may not agree with me. I respect that and their opinions more then I can explain. What I can tell you if from my own personal experience and I have built many engines using "big box" cam companies and in most cases have decent results.

As i stated, I built a stroked 408 with iron small valve heads from a 1973 360 out of a Challenger. I do realize that I could put better head on my engine and make significant improvements to power and ultimately will as budget allows but for now I am very happy. My build made 410hp and 460ft torque at 5800rpm. I cannot tell you how happy I am using Bullet Cams and will absolutely use them from now on with every engine I build going forward.

Sorry for the lengthy response but just wanted to share my opinion with Bullet Cams and how well they took care of me and how well their product performed. I highly recommend giving them a shot.

www.bulletcams.com Tim Langley is who I dealt with. Great company!!!!

 

[yellow rose]

As I posted elsewhere:


Racer Brown
Cam Motion
Jones cam
Bullet cams
Controlled Induction
Chris Straub
Scott Brown

In no particular order.
Most of them don't even do shelf cams, although Cam Motion and Bullet may have some shelf stock cams for 2bbl circle track stuff and the like.

There is never a reason to buy a shelf cam if you are building anything other than a bone stocker.

And that is not all of them. I know Isky will grind a custom cam. Erson is doing more custom stuff. All you have to do is ask. Most of them are a week to 10 days out when you order.

 

[norton]

As I posted elsewhere:


Racer Brown
Cam Motion
Jones cam
Bullet cams
Controlled Induction
Chris Straub
Scott Brown

In no particular order.
Most of them don't even do shelf cams, although Cam Motion and Bullet may have some shelf stock cams for 2bbl circle track stuff and the like.

There is never a reason to buy a shelf cam if you are building anything other than a bone stocker.

And that is not all of them. I know Isky will grind a custom cam. Erson is doing more custom stuff. All you have to do is ask. Most of them are a week to 10 days out when you order.

If you go back and read my original post. I did ask about a cam that was stock or very close to it.

 

[yellow rose]

If you go back and read my original post. I did ask about a cam that was stock or very close to it.

Actually, for the sake of posterity and being correct, your first post asked several things. One was will "this" cam work for my stock 72 340 and the answer yes, you can slide it in, but that thing is way too big for stock valve train. Then you said you don't understand cams. Regardless of what other people agree or disagree with, I didn't see a single post that there wasn't SOMETHING you could learn about cams from. Knowledge is just information. Understanding is being able to use the knowledge you have. I know people that have knowledge base that is a mile wide, but an inch deep. I also know people whole have a very narrow range of knowledge, but what they know is very in depth.

So the answer is nope, that cam won't work for what you want. You don't have the valve train, converter, compression or gear to deal with that cam.

Your best bet is buy a cam that is ground for your application. You will get the best idle, best power and best driveablity that way.

 

[norton]

Actually, for the sake of posterity and being correct, your first post asked several things. One was will "this" cam work for my stock 72 340 and the answer yes, you can slide it in, but that thing is way too big for stock valve train. Then you said you don't understand cams. Regardless of what other people agree or disagree with, I didn't see a single post that there wasn't SOMETHING you could learn about cams from. Knowledge is just information. Understanding is being able to use the knowledge you have. I know people that have knowledge base that is a mile wide, but an inch deep. I also know people whole have a very narrow range of knowledge, but what they know is very in depth.

So the answer is nope, that cam won't work for what you want. You don't have the valve train, converter, compression or gear to deal with that cam.

Your best bet is buy a cam that is ground for your application. You will get the best idle, best power and best driveablity that way.

My car right now has a 340 out of a 1970,that is 30 over, with a Street thumper cam, J heads with 2.02 intake and 1.94 exhaust valves, an RPM, Dual plane intake and a 600 Holley. The trans is a 727, with a B&M 2800 Stall torque and a reverse valve body. The limited slip rear has 355s.
I bought the numbers matching 340 engine and would like to rebuild it to stock, install it back in the car, but not change anything else. This why I'm trying to match a cam to stock specs.

 

[yellow rose]

So you want a cam with 72 specs? Are you going to keep the intake and carb, or use the stock CI intake and Thermoquad carb?

 

[norton]

Going to use the factory intake and thermoquad. Hope I spelled that right.

 

[yellow rose]

Going to use the factory intake and thermoquad. Hope I spelled that right.

I like that induction combo.

If you really want, you can get a 72 cam, and IIRC the stick and autos were the same. If you are not too married to the idea of exactly duplicating the 72, you can call a cam grinder and have them do one up.

Once you get the TQ dialed in those things are awesome.

I'm seriously looking for one of the aftermarket ones and I'm going to modify the Strip Dominator intake I spent 35 hours on back to accept the TQ or I may find another manifold and put a TQ on it.

 

[norton]

I really like the car the way that I, have it now, plenty of get up and go. However I want to drive it across Canada and back next year, about 6000-7000 kms or about 4500-5000 miles. Right now I'm getting 6 miles to a US. gallon. So build a factory spec engine and hopefully get 14-15 miles to a US. gallon.

 

[AJ/FormS]

Well, you could call the nearest Chrysler parts department.
P4452782
This is 268/276/114 with 44* o/lap, and .429/.444 lift.
But I wouldn't take it on tour for that amount of miles, not unless I could afford the gas.If my math is right that would be 7000/14mpg theoretical=500 gUS. At $5.00/gallon, that works out to um oh $2500bucks!
Naw, I'd haul out my 273 or 318 and plug that guy in there for the trip, oh and I'd stick a 2.73 in the back. If I was careful the fuel savings would pay for all the meals and a good part of the motel rooms.
On second thought I'm getting a little old to be swapping engines twice in a month, so I'd just take a CRV or a Kia-Soul,or a Neon,lol. But I guess there's no stylin' in any of those

OOps I see you are Canadian, eh?
In that case you can get 14mpgCan, and it's only 5000miles, and the math spits out; about $2000 Can. The savings a teener offers is only maybe $800C;but it will still buy all your food, and most of a passenger's as well. But I'm a lot less interested in swapping engines for $800smackers.
But I might be interested in installing a more fuel-efficient cam.I mean the 340 is just a big-bore teener right?..... I put a teener cam in one of those once,with the small-port heads. Man that thing took off like a cat on fire! Back then gas mileage didn't interest me as gas was just 37cents a Can.gallon. But Ima thinking with the compression boost of the 340 and the Dcr boost of the teener cam, I bet I could squeeze over 25 out of her. In steady state with the TQ and 2.73s, I bet more. Well maybe only in Manitoba/Saskatchewan where the speed limit is 100kph
Yeah so anyway, the 340 cam is listed at the top.I haven't been to the dealer for parts for a long time, so I can't say if they are still selling Mopar Performance Parts.

 

[crackedback]

Want a cam close to stock but a smidge bigger.

The old 214/224 cam is a good camshaft. You can get them from speed pro CS1019R and some other suppliers. Engine pro mc3203

I had one in a Swinger 340 4 speed car for a long time. Had a little more lope at idle, nothing too aggressive and easy to tune for an auto car. With an increase in converter flash, it would be a good choice. Car ran 13.30 at 102+ with that cam.

 

[AJ/FormS]

Well if we're gonna go that way, I can tell you that a fast-rate 223/230/110 hi-lift cam, when accompanied by a well-matched Dcr, a TQ,headers-with-free-flo-exhaust, and overdrive, can, with a sharp tune,rival fuel mileage of many modern-day V6s, and some 4-cylinders! (And I'd like to know why that is! How is that 25 to 30 years of technological improvements,since the energy crises of the 80's(hah) still can only give us the occasional car with exceptional fuel mileage? And please, don't get me started on hybrid electrics.)
I know this cuz I built one.
And it wasn't hard.
And it went 12.9/106 with a 2.2 60ft, in a street 68Barracuda.
I loved that cam, right to the moment it dropped 2 lobes into the pan, that backstabbing,no-good,pos.,bumpstick,lol.
OOps, I have a 360, and I put over 100,000 miles on it from 2000 to 2010;not many after that, and fewer still after 2014.
I have no way to prove this, but I think the dual,full-length,3inch exhaust has something to do with the numbers.
Jeepers we had 3.7liter engines(225slanties), in Dart-Lites,with all the aero of a brick, that pushed the envelope, in the 70s, getting close to and over 30mpgs(Can). How many similar sized and weight modern cars can boast a significant improvement over that? Where are all the mega-mpg cars they prophesied about?
There is no getting around chemistry and physics. It takes a certain amount of energy to propel a vehicle down the road at 60mph. And that certain amount of energy, takes a certain amount of fuel. And that is the most basic law. You can tweak it abit but you cannot stray far from the law, with an internal combustion engine. So don't hold your breath for a 100mpg gasoline carb on a 3500* car,lol. Or an EFI, or any other gasoline metering device.
But tweaking is fun!