Horsepower has only a little bit to do with pleasant driveability - that is all about TORQUE, and even the 'smog strangled' big-blocks of the mid-to-late-seventies had excellent very low RPM torque. Thus - pleasant to drive, unlike the revvy things nowadays.
The reasons that the 455 Olds was down to only 195 HP by the 1976 model year, were because dual exhausts were no longer available by then, the carburetor was set to run very lean, and the camshaft was very, very mild compared to the high performance cams that the 455 Olds got from the factory in prior years. My experience with that engine was that when it had dual exhausts, adequate carburetor jetting and a really good high lift, long duration cam, it would be putting out close to twice the power of the 1976 engine.
To the writer of the comments above... thank you very much for the clarification... I wondered why an engine that large (455 cu. in) would only command a rather anemic 195 HP; makes complete sense now.
While I've got your attention: does anyone happen to have any advice as to how I could improve my Oldsmobile's gas mileage? I own a 1976 98 Regency, which I have maintained well since purchasing to include a tune up and carb overhaul - the engine is a 455 4bbl - so I don't expect miracles, but 10 MPG is about all I've been able to muster. Any after market additives that anyone uses to improve mileage, etc??? Any help you can suggest would be appreciated very much.
I'm sorry to say, but 10-12 MPG is about the best you'll ever be able to get with the Olds 455. There's really no way around it, except for buying a smaller, more efficient car.
My Chevelle gets 8.5 MPG and I could care less. 10-12 in a large GM like this one is par for the course as far as MPG. I add Techtrol a couple of times a year in my cars; not for MPG, but to clean up the fuel. I also use Startron for the ethanol breakup prevention. The engines run smoother.
As far as the 455, which I don't have, like in Pontiacs, Buicks etc, they were very potent, especially in the 69-70 era. Between the insurance companies and Government, the later 70s was a abysmal period for HP. Fortunately times are bright today with performance and MPG gains.
To 15th Oct 2013, 23:02 from 4th Sep 2013, 15:10
To get better mileage from the 455, try advancing the spark timing & use the highest octane gas you can get. I once had a 1972 442 with a 455 that gained approx. 2 MPG by doing that.
In my experience, that's about all you can do to improve a 455's gas mileage. Keep in mind the fact that the last thing that the 455's designers intended it to do was to get good gas mileage.
Thanks for the suggestions everyone... I'll just keep my foot off the accelerator a bit and try not to open up the four barrels as often. Ha ha.
Most large cars from the 70's will not get very good mileage. In fact most V-8's from even the late 80's do well to get over 12-14 MPG. My last 5.0 Mustang got between 9 and 15 MPG. Modern engines are far more efficient. Still, I envy anyone lucky enough to own a nice large Old from the 70's. They were incredible cars that last virtually forever.
My 1980s large V8 cars easily got 20 MPG or more. Oldsmobile 307s and Chevrolet 305s. The reason no doubt was high gearing and overdrive transmissions.
My first car in sales was a 1968 Olds Cutlass with just the 350 automatic. Rode nice and never let me down. Gas was only 30 cents a gallon then. In that time MPG was not even a concern. It was also great before the anti pollution and smog devices made vehicles a disappointment to own. HP was close to 300; later the 350 V8 dropped to 190-220 HP.
My 69 SS Camaro was 350 300 HP. My 70 Z/28 Camaro was 350-350 HP. My current 70 Chevelle SS is 396 350 HP. After 70 it went down and down til late 90s to present, with many LS engines being transplanted into older ones as well.
I own 2 '76 Ninety Eight Regencys (both coupes) and they are incredible automobiles. While they are not ideal for daily driving around town, especially in smaller areas with lots of stop 'n go, the mileage can be quite impressive on the open road.
One of my cars has the 2:41 rear and I upgraded to a true dual exhaust. We take that car on most of our vacations, even very long trips (with no trouble whatsoever mind you) and I have gotten in the mid-to-upper teens with it. I got just shy of 19 MPG once coming back to CT from North Carolina. That's damn impressive to me for a 5,000 lb car sailing down the highway at 75mph with a trunk full of luggage, 2 mountain bikes and the A/C on!
These cars are made for the open road, and there is nothing else like them for a good highway run.
You don't buy these cars if gas is a concern. I get 8.5 MPG in my muscle car. I could change the rear and bump up a few MPG, but I have a big block, so what's the point in losing what the car was made for. A big car like this can take the family on a trip. And split the gas. I owned a limo and it got terrible mileage. But it was awesome to take on a trip.
If one wants the same level of comfort and nearly the same size, but much better mileage, just look into the early 1980s Oldsmobile 98s. They had a 307 and a 4 speed overdrive transmission. With the high gearing, the mileage was quite good - I believe I got in the very low 20s MPG consistently with my Delta 88 during mostly highway driving and with an extremely light foot. As the saying goes - 'drive like there's an egg under your foot'.