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Need Help in Getting Better Gas Mileage

  #1  
Old 05-29-2012, 06:02 PM
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Default Need Help in Getting Better Gas Mileage

Hi Everyone,

We have a 350 engine in an '87 LS. It runs smooth but it's our 1st 350 (came with the car) and it goes through gas like I've never seen. I've had '80's Montes with the 305 engines in the past and they did at least double the gas mileage. I was told headers and dual exhaust would help, which are on our horizon. Carb is adjusted too. Is there anything else we can do to help save gas? It's costing a fortune to drive her!

Thank you!!!
 
  #2  
Old 05-29-2012, 06:13 PM
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put it in the garage and buy a geo. jk but yea that would be best option. Or you can "update" your engine and swap out yours for a 350 vortech. My moms vortech gets 23 mpg in a yukon so in a monte you would get 25 at least.
 
  #3  
Old 05-29-2012, 06:19 PM
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What kind of carburetor is on it? If it's a Holley or something similar, then you'll never get great fuel mileage with it. Yes, headers and exhaust will help tremendously, but most aftermarket carbs just don't do that well on fuel economy. Yes, Quadrajets are a pain in the butt to tune properly, but if they're tuned correctly you can't beat them for the combination of performance and fuel economy. I still have the stock Q-jet on my 73 Camaro and it will flat out scoot and I still get 22mpg with a .82 5th gear. Once I swap in a 6 speed for the 5 speed in there, I'll probably get closer to 25mpg on the highway.

Is the transmission an overdrive one? If not, then an OD swap may be in your future if you want to take a real stab at fuel economy. If so, then start with the exhaust and work from there. You may have to go away from the aftermarket carbs in the end.

Hope this all helps!
 
  #4  
Old 05-29-2012, 06:21 PM
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Originally Posted by Mr Grizzly Mint
put it in the garage and buy a geo. jk but yea that would be best option. Or you can "update" your engine and swap out yours for a 350 vortech. My moms vortech gets 23 mpg in a yukon so in a monte you would get 25 at least.

Truck intake won't fit under a car hood. We deal with this all the time in the Camaro world. Plus they'd have to replumb their fuel system and possibly modify their fuel tank to keep from starving their engine when under 1/2 a tank.
 
  #5  
Old 05-30-2012, 08:00 PM
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Originally Posted by SupplySgt
What kind of carburetor is on it? If it's a Holley or something similar, then you'll never get great fuel mileage with it. Yes, headers and exhaust will help tremendously, but most aftermarket carbs just don't do that well on fuel economy. Yes, Quadrajets are a pain in the butt to tune properly, but if they're tuned correctly you can't beat them for the combination of performance and fuel economy. I still have the stock Q-jet on my 73 Camaro and it will flat out scoot and I still get 22mpg with a .82 5th gear. Once I swap in a 6 speed for the 5 speed in there, I'll probably get closer to 25mpg on the highway.

Is the transmission an overdrive one? If not, then an OD swap may be in your future if you want to take a real stab at fuel economy. If so, then start with the exhaust and work from there. You may have to go away from the aftermarket carbs in the end.

Hope this all helps!
Hi, it does have overdrive which I'm very good about using when I switch from around town to highway driving. But it does also have a Holley Carb which I would not mind parting with. How would I go about a Quadrajet conversion?

Thank you so much!

P.S....I "inherited" a GEO Metro years ago...it was unreal on the gas conservation, however I don't think I want to go back to that! lol
 
  #6  
Old 05-31-2012, 07:16 AM
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You'll need a q-jet carb, the correct intake manifold for it and all that. It's very tedius to tune and isn't plug and play, but it has a very good mix of economy and performance. Another thing to think about in the meantime, what CFM is your Holley? Anything above 650 is probably too much for your purposes and could also be playing a big role in why you're getting terrible fuel economy. You may have too much carb for your motor. That's the beauty of the Q-jet though, is that because of the way it works, it's basically like having a variable CFM carb.
 
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