400 vs 440 in a 76-78 New Yorker - noticeable difference?

[commando1]

I just got my Gran Fury on the road and it has a bone stock 400 HP engine, aside from a Holley 4011 carb and points ignition instead of lean burn, 3.21 gear, and it'll spin the tires about 15 feet out from a dead idle taking off. It's a heavy beast so the actual performance isn't that impressive but it feels and sounds like it has power. Not sure how much stronger the police spec 4 barrel 400 is than the regular 2 bbl, but I'd consider it quite adequate for having fun. It does way better than my R body 318 HP Gran Fury, which has a 2.94 gear and will only chirp the tires if you rev it up against the converter before launching, and doesn't plant you back in the seat nearly as much.

Also those mileage numbers are insane. The best I've gotten the 318 4 bbl to do is 18 mpg on the highway running 55, and it has a lockup converter and MSD ignition. Even my slant 6 Aspen struggles to get 22 mpg. How on earth can a big block compete with them? What's going on with my cars to make them so much worse? Granted my "highway" mileage does involve a few stops here and there navigating to my destination but still.

Was the cop 400 swapped into the car?
I don't think it was available for civilian cars.

 

[70bigblockdodge]

Also those mileage numbers are insane. The best I've gotten the 318 4 bbl to do is 18 mpg on the highway running 55, and it has a lockup converter and MSD ignition. Even my slant 6 Aspen struggles to get 22 mpg. How on earth can a big block compete with them? What's going on with my cars to make them so much worse? Granted my "highway" mileage does involve a few stops here and there navigating to my destination but still

Terrain and stops and starts, as mentioned stop and starts kill mileage. Takes energy to accelerate a mass back to a speed.

 

[Just Carbs]

The 400 is fine for steady cruising at 75 on the highway and stop and go traffic around town.
The 440 has much better part throttle response.
The difference is very noticeable getting up to speed for merging at 60 to 80 and for passing on two lane roads at 45 to 60 and for climbing through winding mountain roads at 40 to 60. The 400 doesn't like doing any of that. The 440 generally does it in 3rd gear part throttle no down shift.
Also, big difference in wide open throttle acceleration.
My 1976 is a 440. No lean burn. Stock ignition. Carter replacement carb, it's ok. Dual exhaust, slight drone.
The 400s do run well, but with less of what the big cars need.
Get the 440.

 

[6PKRTSE]

I have had (3) 440 and (5) 400 73-78 C Bodies and all (3) 440s car were definitely noticeably quicker that the 400 cars even though they were more loaded up with options which adds more weight. Although none of them are/were race car fast.

 

[1975.Imperial]

Here's the horsepower/torque curves for a '77 NYB with either a 440 or 400 (courtesy of automobile-catalog.com). As seen here, the 440 would have more low end torque, but the 400 seems to catch up after around 3,000RPM.
The factory power specs are tuned for emissions compliance, with lazy timing, overly lean carburetors, and a variety of vacuum actuated emissions junk. You could actually get much better performance just by tuning them right and getting rid of the emissions stuff.
With these cars approaching 50 years old now, one other important thing to consider is the condition of the engine, a worn out 440 won't be able to keep up with a brand new 400.

My '75 Imperial has around 90,000 miles on it's 440 (emissions deleted & tuned decently) and although it's slow in a drag race, it's able to keep up with traffic around town, and even on the freeway. I just find that it needs about 50% throttle input to match any new car's 30%, but in a world where new cars rarely exceed 50% throttle input, I still have a high enough throttle ceiling to keep up

 

[furious70]

Have to face the facts, they will both will get smoked by a late model Camry

 

[PursuitSpecial]

Was the cop 400 swapped into the car?
I don't think it was available for civilian cars.

It's the original engine for the car, the vin is on it. It was originally an undercover police car, the fender tag says it has the A38 package with an E68 engine and it was a special order body in white. But it doesn't have roof light wiring and was painted the color it currently is from the factory which is why I'm assuming it was unmarked.

 

[WissaMan]

Thanks for the dyno plots, they are very insightful. Though it says they are approximations. I wonder how they come up with them?

 

[Mort St. John]

I've been rolling around in my head getting a 76-78 New Yorker for road trips. Some of them have the 400, some the 440. Of course I'd want the 440 but is there going to be much of a noticeable difference in power, assuming they are both running correctly with a most-likely deleted ELB? I know neither are going to be real peppy as compared to my 68.

I don't really want to do any performance mods except maybe an aluminum intake, carb, and (quiet) dual exhaust

I had a 1977 with the 440 a few years ago and have a 1978 with the 400 now. I do not notice much difference. Let's face it, neither one had a whole lot of power, but both will happily glide down the freeway all day at slightly over the posted speeds. That keeps me happy.