Now, I've trolled this forum for a bit and I'm fully aware of the V8 flames that are coming.
I've got a 1979 Buick LeSabre with a Pontiac 301 (4.9L) V8. This beast weighs in at around 5000 pounds (according to driver's door stickers.) Not sure on the transmission type, but it's either a TH200 or TH350 3 speed automatic.
By this point everybody must be thinking it's a gas guzzler and I should dump it for a much smaller car. Well, on the contrary, this car is actually quite fuel efficient for it's age and type. My best recorded trip was a 116 mile trip with a 25 mpg average. This was at a constant 60 mph for the first 80 miles, and through rush-hour traffic on a Saturday for the next 36 miles.
Since then I've taken half the exhaust off to offset the fuel required for warming it up in the winter. The original owner had the catalytic converter taken off, for whatever reason. So now I'm running with an open exhaust after the headers, with no muffler. The car is surprisingly quiet despite not having a muffler, and is still just as clean burning as it was before. (Due to the cat already being removed)
Around town I'm averaging from 17-20 mpg, and on the highway I'm getting around 21-23 mpg. Highway traffic now is slow going due to the winter weather, so I'm not getting as much mileage as I should.
In the near future I'm going to be reassembling the exhaust, this time with full 2.5" piping, a cat, and a magnaflow straight-through muffler. This will be a huge improvement over the stock system which trimmed down from 2.5" piping at the headers, to 1.75" at the tailpipe. I'm also keeping the stock design, which has the piping wrap around the rear axle, in the interest of preserving torque over a straight-piped design.
As far as emissions, which I am still concerned about (HC's and NOx's. CO2 as the main drive for global warming has been proven to be a crackpot theory by the global science community), this V8 was the only GM-made V8 that conformed to ALL emission standards for 1977-1981. It went a bit under the standards, in fact. But due to GM corporate mandates, Pontiac was forced to stop making V8's.
I'll also look into my gearing in the future and let you guys know. My torque peak is at 2000 rpm, and that's usually where I'm at when cruising 55-60 mph. I've got 265/70/15 radial tires all around.
So, let the V8 flames ensue. But I'm proud of this little small block, and I'm sure this will provide hope for the rest of us with classic cars that are still concerned about fuel savings.
