1983 gmc Sierra classic with 305 4X4 gas mileage?
I just bought my first vehicle and it's a 1983 gmc Sierra classic with a 305 engine and it's a 4X4. I'm not super concerned about its gas mileage since I bought a truck, but I just want an idea since I won't be driving another year because I'm 15. Thanks.
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Estimate 10
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1983 gmc Sierra classic with 305 4X4 gas mileage?
I just bought my first vehicle and it's a 1983 gmc Sierra classic with a 305 engine and it's a 4X4. I'm not super concerned about its gas mileage since I bought a truck, but I just want an idea since I won't be driving another year because I'm 15. Thanks.
1983 Gmc Sierra
1983 Gmc Truck
A big variable will be what transmission it has and what 'rear end' ratio it has. With the 305 it was not likely to have a really tall rear which is a good thing when it comes to MPG. Not so good for towing and hauling but if someone planned on towing they would have likely got a 350 or 6.2 diesel. If got the 3.42 or 3.73 and the automatic with overdrive which was available then you may see 15 mpg. If its just the 3 speed auto or manual or has say 4.10 gears 10 is likely a good guess.
I would not waste time and money on throttle spacers, cat back systems or free flow air cleaners. At full power, they MIGHT help. Dyno testing shows little actual gains at full power and that is NOT what you are after. Check what axle ratio you have. If you have a numerically high number like 4.10, that will kill mileage. The lower,,numerically the number the slower the engine turns and the better the economy. Nest time you change tires, see if you can increase the diameter a LITTLE and recalibrate your speedometer. Electric fans would help reduce parasitic losses of the mechanical fan. BUT one big enough for your engine is NOT cheap and might require an alternator upgrade. The strongest electric fan at a reasonable price I know if is on the mid 1990's Taurus..Yes Taurus, but at high speed..was two speed, it take 50 amps to run. Good Luck
agree with 10 or so mpg.. but my recommendation is to take that year and yank the 305 out and put the 350 4 bbl in it instead.. the 305 is a dog of a motor and basically junk.. the 350 was an option and should almost bolt right in without too much hassle, and it will be reliable and much more powerful