Getting more power in a C body

[330dTA]

QUOTE "I like the 2,76 rear end due to the comfy rpm at highway speeds so we would probably want a torque monster more than a high HP "musclecar engine". Gas mileage counts too, right?"

I find that statement a bit confusing. Which one are you after, gas mileage, or "get up and go" kind of performance? With these cars, with their engines, it is impossible to have both.

As far as I have understood, your car has the 383 engine with 2 barrell carb. With the 2.76 rear end it is the best option for gas mileage. Not difficult to get as low as 12 L per 100km. But performance wise it will always be "granpa's car"; about 10 seconds 0 to 100 kph.
Switch to a good 650 cfm 4 barrell (a Thermoquad, for instance), and it will wake up quite a bit. That alone will cut perhaps 1 second off the 0-100 kph time.
If it already has a 4 barrell, then change the rear end to 3.23, which will wake it up a bit more.
Better still, put a 3.55 rear and a Gear Vendor to it, and you will have the best of both worlds: fairly decent gas mileage, and nice off the line performance.

I will not touch on the subject of engine mods: those have been discussed above, and then we would be talking about much bigger investments. - That 383 you have is a fine engine as it is. It revs easily, and with very subtle enhancements (the carb and the intake) it will give decent enough power.

(I have a fresh 440 with a 2.76 in my '70 NYer Coupe, and it runs with 14.1 L/100 km, i.e. gets 16.8 mpg on a longer tour, at a steady 110 kph/68 mph. Around town, pushing the gas pedal often, it easily eats 28 L/100km i.e. gets only 8.4 mpg. But because of that 2.76 rear, it is slow off the line. I'm planning on that 3.55 plus Gear Vendor swap.)

 

[Norwegianmopar]

QUOTE "I like the 2,76 rear end due to the comfy rpm at highway speeds so we would probably want a torque monster more than a high HP "musclecar engine". Gas mileage counts too, right?"

I find that statement a bit confusing. Which one are you after, gas mileage, or "get up and go" kind of performance? With these cars, with their engines, it is impossible to have both.

As far as I have understood, your car has the 383 engine with 2 barrell carb. With the 2.76 rear end it is the best option for gas mileage. Not difficult to get as low as 12 L per 100km. But performance wise it will always be "granpa's car"; about 10 seconds 0 to 100 kph.
Switch to a good 650 cfm 4 barrell (a Thermoquad, for instance), and it will wake up quite a bit. That alone will cut perhaps 1 second off the 0-100 kph time.
If it already has a 4 barrell, then change the rear end to 3.23, which will wake it up a bit more.
Better still, put a 3.55 rear and a Gear Vendor to it, and you will have the best of both worlds: fairly decent gas mileage, and nice off the line performance.

I will not touch on the subject of engine mods: those have been discussed above, and then we would be talking about much bigger investments. - That 383 you have is a fine engine as it is. It revs easily, and with very subtle enhancements (the carb and the intake) it will give decent enough power.

(I have a fresh 440 with a 2.76 in my '70 NYer Coupe, and it goes with 14.1 liters per 100 km on a longer tour, at a steady 110 kph. Around town, pushing the gas pedal often, it easily eats 28 L/100km. But because of that 2.76 rear, it is slow off the line. I'm planning on that 3.55 plus Gear Vendor swap.)

What I mean is that with more power, especially torque, the engine works easier, or less hard if you will, keeping the car moving which again is good for gas milage. It will also be able to accelerate a bit faster and with less effort. It will have more power than it needs basically.

If we attach a trailer hitch and pull a camper (like we would love at some point) that extra power will be good to have also. Less effort to move the car and camper.

As we speak we are already in discussion with my buddy and Mopar supplier about building a stroker for it, either from a 383 or a 440. A shift kit for the trans and an oil cooler is also on the list.

We don't intend or expect it to become a pure musclecar in any way, but a bit more power than today wouldn't Hurt.

 

[furious70]

An engine working "less hard"?
If you mean a throttle less open, that is less efficient as there's more pumping losses having to draw the same cfm air through a small slit vs a larger opening.

 

[Norwegianmopar]

An engine working "less hard"?
If you mean a throttle less open, that is less efficient as there's more pumping losses having to draw the same cfm air through a small slit vs a larger opening.

I mean having to use less percentage of it's power to move the car. It's a reason why a V8 powered car can be more fuel efficient than a V6 or I4 in the same car. With lots of torque higher rpm isn't needed to use the power more efficiently, it's a more economical use of the engines power if you like.

 

[furious70]

But that's not really true. The smaller displacement will be more efficient at low demand steady state given the engines themselves have similar efficiency

 

[Retired auto tech]

The best all around rear gearing is the 3.23, especially if you intend to tow with it. Anything less you will be struggling to get up and go and using way to much thottle opening just to cruise with a reduction in fuel economy by a lot. The purpose of any gear ratio is to multiply torque. The correct ratio for the intended purpose should see the engine rpm turning at just under the middle of the torque band. This will give the best economy as well with the engine running free without working hard just to maintain cruise speed. I once experimented with a Ford E150 van that came with 2.75 gearing from the factory. When climbing a slight grade with the cuise control on the engine vacuum would drop to 7 or 8 inches of vacuum opening the power valve and dumping extra fuel in even when not needed. Changing the rear end to 3.0 raised the vacuum to 12 inches preventing the power valve prematurely opening. Improved the acceleration but best of all it gained over 5 miles to the gallon. A gear ratio change will feel as if you've added at least a 100 lb ft of torque without touching the engine and should be the first step to consider and then tailor the engine mods to match.

I just recently obtained a 67 New Yorker parts car and will be using the 3.23 sure grip in it for my 67 New Port convertible. For $500 it was a bargain as it also has Auto Pilot, A/C, tilt and telescope wheel, sentinal lighting, power vent windows, year correct 440 and trans, a good front bumper, 3 speed wiper motor, 3 inch front brakes, a useable dash pad, and a zillion other little bits and pieces. If I am lucky I might even get some of the floor pan pieces I need as well.

One man's junk is another's treasure.

 

[Norwegianmopar]

The best all around rear gearing is the 3.23, especially if you intend to tow with it. Anything less you will be struggling to get up and go and using way to much thottle opening just to cruise with a reduction in fuel economy by a lot. The purpose of any gear ratio is to multiply torque. The correct ratio for the intended purpose should see the engine rpm turning at just under the middle of the torque band. This will give the best economy as well with the engine running free without working hard just to maintain cruise speed. I once experimented with a Ford E150 van that came with 2.75 gearing from the factory. When climbing a slight grade with the cuise control on the engine vacuum would drop to 7 or 8 inches of vacuum opening the power valve and dumping extra fuel in even when not needed. Changing the rear end to 3.0 raised the vacuum to 12 inches preventing the power valve prematurely opening. Improved the acceleration but best of all it gained over 5 miles to the gallon. A gear ratio change will feel as if you've added at least a 100 lb ft of torque without touching the engine and should be the first step to consider and then tailor the engine mods to match.

I just recently obtained a 67 New Yorker parts car and will be using the 3.23 sure grip in it for my 67 New Port convertible. For $500 it was a bargain as it also has Auto Pilot, A/C, tilt and telescope wheel, sentinal lighting, power vent windows, year correct 440 and trans, a good front bumper, 3 speed wiper motor, 3 inch front brakes, a useable dash pad, and a zillion other little bits and pieces. If I am lucky I might even get some of the floor pan pieces I need as well.

One man's junk is another's treasure.

Yes I agree about the rear end gearing, I think we will go with a 3.23 when we get the new engine.

It sounds like you did very well on that New Yorker!

 

[Retired auto tech]

Yea it was a great find. About the only options it did not come with was am/fm radio, Speaker reverb module, Cornering lights, bucket seats, and console shift. The fender tag even has two catagories for Unknown Options (w3) and (d7) which must cover for the power antenna, auto pilot and remote trunk release which do not appear anywhere else. It also says that this car was a sold car when it was built. The one big surprise was when I noticed that the all the rocker trim was in good restorable trim and is the same as the New Port except that the raised portions are painted where as the New Port has the spaces inbetween painted. This is great as mine are totally destroyed from gravel roads. It was found on a farm in a horse pasture and it seems that horses consider convertible top a delicacy.

 

[BigWally]

Dude, you are in Norway, and doin all this ?!?! You are offically the coolest guy in Norway!!

 

[Norwegianmopar]

Dude, you are in Norway, and doin all this ?!?! You are offically the coolest guy in Norway!!

Well first of all thank you do much! Yes I am in Norway, but american cars are a big thing over here and the quality of the cars is quite good tbh. However, our 67 is a one off (as it would be anywhere) due to our custom touches such as removing the side moldings, painting the roof etc. We are in the process of planning the interior which will be all redone this winter as well as the engine which will be replaced by a built stroker eventually. But we do love the car as it is and all the attention it gets!

 

[Gerald Morris]

I have been playing with the idea of maybe getting a done engine and trans (with extra cooler) and just put aside the original ones for a later rebuild. A 440 would probably be the best choice considering cost vs power. A stroked 440 would be even more fun.

We don't want it to behave like a choppy musclecar, but rather have the best of two worlds - a comfy cruiser but with enough power to mess with the street brawlers if "needed".

Decent gas milage and rpm at highway speeds counts too since gas is pretty expensive here in Norway (3-4 × US cost).

I have also thought about this car not being that much heavier than a B body so it should be able to get pretty good performance if wanted.

IFF you want good petrol "kilometerage," and performance, an RB block engine will give more torque with all other factors equal, from the greater stroke. Then, KEEP YOUR 2:76 REAR END RATIO! Keep the small exhaust valves too. Closed quench heads with small exhaust valves were DESIGNED to deliver a low rpm curve. Where you will enhance performance will be with fuel injection. I suspect there are more modern closed quench heads which should accommodate EFI. Much as I loathe reliance on computers, if you REALLY want EFFICIENT use of engine resources, design your engine for EFI, optimizing the power band and torque for lower angular velocity.

One might forego EFI with good CD ignition, allowing you to retain the iron heads. Dual exhaust CERTAINLY helps. I put one on my 1965 built 383, and even with worn out heads, the dual pipes allowed the engine to breathe better, launching from traffic signals with a bit more grunt.

I really should hit up the NSF or a Fed agency for a modest couple megabucks for deep R & D on a C body Mopar, comparing optimized B/RB engines with a couple electric drives!

 

[furious70]

But that's not really true. The smaller displacement will be more efficient at low demand steady state given the engines themselves have similar efficiency

So that other's reading aren't confused, would you mind explaining why you disagree with my comment?

 

[Just Carbs]

The little engine program can work fine if you have a shift happy transmission with enough gears to keep it at the optimum rpm (3000/4000?) all the time.
But that's just not what big block C bodies are all about.

On the other hand, my 4800 pound 300 hp 98 NORTHSTAR (still ain't blowed its heads off yet) Deville gets 18/26 mpg, does 0/60 in 7 seconds, and spins a lazy 2500 at 75 mph, with 2.95 rear. That's about exactly the same as what my 5000 pound 96 Buick Roadmaster cast-iron 350/chevy powered wagon does with 2.95 rear.

And of course, my 2500-pound 2004 New Beetle 2.0 automatic trans "lives" at 4000rpm, gets a whopping 18/24 mpg, goes 0/60 in a SCREAMING twelve seconds, and spins 4000 at 75 mph.

If I had a really nice C body with a blown-up motor and trans, I would for sure be reading up on a newer motor/trans combo transplant.

Because go-fast "and" mpg ain't part of the Mopar big block C body program.
Wrong everything. Heads, cubes, induction, ignition, brainpower, trans,,,,,,,,, just everything.

 

[Norwegianmopar]

So that other's reading aren't confused, would you mind explaining why you disagree with my comment?

Sure. A smaller engine will need higher rpm to move the car efficiently and more gears like Just Carb said over here. Here in Norway we have a lot of cars with low output and small displacement because they are cheaper tax wise (tax and vat is determined by emmissions, displacement, horsepower etc), so a lot of new cars have the smaller engine options as a result. However, even tho they are cheaper to buy, they are not neccessarily cheaper to use since the smaller engines must work harder to move the car. If you also pull a camper, which a lot of families have over here, the difference is even higher. This is a very well known fact. Diesel engines are very popular due to the power vs consumption ratio and many are tuning them (chipping) for more power and also lower consumption. Our 2017 Volvo XC60 has a 5 cyl diesel (D4) wich came with 163 HP (the "budget" engine power wise). We did a Polestar tuning (original from Volvo) which gave it 215 HP and a little more torque. The result? More power and lower consumption. The 4 cyl versions might be cheaper on flat roads under little to none resistance, but going uphill or pulling a loaded trailer the smaller displacement is an disadvantage. A long read but that's how I see it.

 

[furious70]

Let's use engineering and science, not how we see it.
You've changed the efficiency of the engine you mention, not the displacement.

 

[Norwegianmopar]

Let's use engineering and science, not how we see it.
You've changed the efficiency of the engine you mention, not the displacement.

Yes it was a small digression, but the point was that this engine runs more efficient than it's siblings with the smaller engines and less power/torque.

Anyways, from my own experience, a bigger and stronger engine works easier than a smaller one under load.

 

[69PHOENIX]

G'Day,
Just a Thought!
Gear Vendors & a Set of 3.77 Gears.(2.94 Final Drive)
Maybe a Truetrac as Well, Just for Fun!
Regards, Tony.M

 

[330dTA]

I'm getting the picture now. Of course a big stroker engine will be more fun. With a nice 496 or 512 stroker the Newport will easily run low 14's at quartermile. Perhaps even faster, depending on the build. Which means passing a 24 meter truck on the highway happens in seconds. Easy peasy, that is. But by then one can forget any talk about fuel economy.

 

[Retired auto tech]

Just a note on small v/s big. Back about 25 years ago I had a 1997 Ford Explorer with a 302 FI and averaged 600 km on a tank of fuel. That was driving from Edmonton to Kelowna going though the Rocky Mountains. One of the guys I worked with had the same 97 but with the 4.0 l V-6. He could only get 350 km to a tank driving on the flat. In the mountains he had to stop at every gas station.

 

[75LandYacht]

Remember, i drive this car year round, i just drove it to work this morning, 30 miles one way. I drive it to the drag strip 80+miles one way, and i take the girlfriend out tofancy dinners in it. It makes all the gals at the lodge jealous. It has great throttle response, tons of torque and plenty of horsepower.

Would LOVE for my 77 440 to sound like that.. lol