Fuel milage

[dave69]

I have a 69 chevy pick up 1/2 ton with good running 350 was overhauled before I bought it a year ago and it is stock. I have headers with flow master exhaust, HEI ign.,600 vacuum sec. Holley on Edlelbrock manifold, and a large K&N filter. It runs great every day cold or hot, just if I could get better fuel milage with out spending a lot on Fuel injection that be great. I was thinking of going with stock TBI swap but dont know if I will improve the milage a lot. In Canada we are paying over $4. a gallon we get hosed up here. If I have to spend thousands whats the point. Any thoughts? Thanks

[69GMCLonghorn]

Originally Posted by dave69

I have a 69 chevy pick up 1/2 ton with good running 350 was overhauled before I bought it a year ago and it is stock. I have headers with flow master exhaust, HEI ign.,600 vacuum sec. Holley on Edlelbrock manifold, and a large K&N filter. It runs great every day cold or hot, just if I could get better fuel milage with out spending a lot on Fuel injection that be great. I was thinking of going with stock TBI swap but dont know if I will improve the milage a lot. In Canada we are paying over $4. a gallon we get hosed up here. If I have to spend thousands whats the point. Any thoughts? Thanks

You'll have to spend thousands... no point!

Seriously, though, let's think about it. Brand new trucks today aren't even getting 20 MPG. They advertise 20 or 21, but real world is more like 16 - 18 in most cases. With our trucks, the main thing to work on is dialing in the gearing. Most are taching too high on the highway and use too much gas. If you add gears or change the rear end gears, you can make some decent changes in mileage. But unless you get hooked up with a lucky junk yard find, you'll be spending quite a bit to do anything that will net you a noticeable difference.

You've got it running as well as you can with the parts you've listed. The TBI won't do squat. I'll take a 600 Holley any day. It's a 40 year old truck. Just drive it easy and enjoy it. I mean heck, you don't have payments, right?

[Jim_PA]

Qjet, as always will give you better mileage

[PanelDeland]

Fairly cheap and somewhat effective way to better milage is to go easy on the throttle.Another factor is tire size.A taller tire will help to increase milage a little.Other than that an OD tranny or rear gears is about the only way to get much better milage.Just go up a series in tire when you need new ones.

[dave69]

Well said no it's paid for and it runs better than some new trucks. I do have 3:08 gears with t350 so maybe what I have ant so bad. I have heard of the TPI getting up to 25 to 28 mpgs. Thought TBI to keep it looking old school.
One thing with the holley carb, it is only 9months old and if I drive it too long with out getting into the 4 barrels the gas must get old because it will flood like crazy from the secondaries until I drive it hard than it runs like a champ again. I drive in heavy traffic every day so some time hard to get on it. Plus milage goes in the tank. Thanks from your commets.

[cdowns]

what are you getting for fuel milage and what are you looking to get as far as increase?

[unclewatts]

Originally Posted by Jim_PA

Qjet, as always will give you better mileage

X2 from the Q-jet crowd!!

[dave69]

Originally Posted by cdowns

what are you getting for fuel milage and what are you looking to get as far as increase?

well being old school and we use the damm metric system I have to convert everything over and I think if I did the convertion right around town 10 to 12 mpg. Not sure what I want just would like it to be better.

[dave69]

Originally Posted by 69GMCLonghorn

You'll have to spend thousands... no point!

Seriously, though, let's think about it. Brand new trucks today aren't even getting 20 MPG. They advertise 20 or 21, but real world is more like 16 - 18 in most cases. With our trucks, the main thing to work on is dialing in the gearing. Most are taching too high on the highway and use too much gas. If you add gears or change the rear end gears, you can make some decent changes in mileage. But unless you get hooked up with a lucky junk yard find, you'll be spending quite a bit to do anything that will net you a noticeable difference.

You've got it running as well as you can with the parts you've listed. The TBI won't do squat. I'll take a 600 Holley any day. It's a 40 year old truck. Just drive it easy and enjoy it. I mean heck, you don't have payments, right?

What gears should I look for 3:73?

[Longhorn Man]

10 to 12 is dead on average http://67-72chevytrucks.com/vboard/s...d.php?t=172346

[vectorit]

How much of your driving is on the open roads? I meen highway speeds?

If you spend a lot of time in the highway speed, then maybe consider installng an overdrive unit or a newer transmission with more gears?

[dave69]

Originally Posted by vectorit

How much of your driving is on the open roads? I meen highway speeds?

If you spend a lot of time in the highway speed, then maybe consider installng an overdrive unit or a newer transmission with more gears?

Not much time at highway speeds some days I crawl to work,on the highway traffic in the Vancouver area sucks

[67ChevyRedneck]

You're not going to see much of a difference with a 700R. I "average" about 11-12mpg with my 700R "in town." I do get 15-16 highway, but like you, I don't drive highway often. For a 700R to work well in these trucks the cheapest rear gear option is the 3.73. The 3.08 is too high for a 700R in my opinion (and quite a few others). So you really wouldn't see any improvement at all during your typical drive. For what you drive, in my opinion, your current set up is about the best it can be.

Anyone getting 25-28mpg (in US measurement) with a TBI is completely full of crap. I don't know the converstion, but I know the Canadian gallon is bigger than the US gallon, even so, that seems high. 10-13mpg "city" is just about normal for ANY full size truck with a small block V-8 with just about any trans/rear end combo. The big difference is highway.

[dave69]

Originally Posted by 67ChevyRedneck

You're not going to see much of a difference with a 700R. I "average" about 11-12mpg with my 700R "in town." I do get 15-16 highway, but like you, I don't drive highway often. For a 700R to work well in these trucks the cheapest rear gear option is the 3.73. The 3.08 is too high for a 700R in my opinion (and quite a few others). So you really wouldn't see any improvement at all during your typical drive. For what you drive, in my opinion, your current set up is about the best it can be.

Anyone getting 25-28mpg (in US measurement) with a TBI is completely full of crap. I don't know the converstion, but I know the Canadian gallon is bigger than the US gallon, even so, that seems high. 10-13mpg "city" is just about normal for ANY full size truck with a small block V-8 with just about any trans/rear end combo. The big difference is highway.

No not that high with TBI guys were swapping over to Tune Port Injection. Getting better milage with that set up I just want to keep it old school hidden under the air filter Also we don't go by the canadain gallon anymore it's liters than convert to us.

[mclairmo]

Drive as if there was egg under the accelerator pedal and your goal is to not crack/break it.

[Indyuke]

Ya, biggest thing that saves gas is driving habits.

From there you can play with gearing, tire sizes, etc. Here's what I did to mine, just for a comparison.
- 350 engine
- q-jet with the mains jetted two sizes smaller
- 700-r4 trans
- 3.73 rear gearing
- stock tire size. No wide tires
- all synthetic fluids. (it does matter. Sometime you can see from 2-4mpg improvement just by doing this)

All this gives me about 14mpg in town and 17-18 on the highway... no better than the newer trucks get.

[Jim_PA]

Originally Posted by Indyuke

Ya, biggest thing that saves gas is driving habits.


All this gives me about 14mpg in town and 17-18 on the highway... no better than the newer trucks get.

Yeah, but look what you're competing with. Nice work

[dave69]

Originally Posted by Indyuke

Ya, biggest thing that saves gas is driving habits.

From there you can play with gearing, tire sizes, etc. Here's what I did to mine, just for a comparison.
- 350 engine
- q-jet with the mains jetted two sizes smaller
- 700-r4 trans
- 3.73 rear gearing
- stock tire size. No wide tires
- all synthetic fluids. (it does matter. Sometime you can see from 2-4mpg improvement just by doing this)

All this gives me about 14mpg in town and 17-18 on the highway... no better than the newer trucks get.

Thanks that milage doesn't seem bad at all. I will work on it over time. I have a posi to in stall so I will track down gears and trany. I don't drive it hard at all. Just nomal heavy traffic.

[UltraBlue71]

Q-Jet x4

[Myself]

An aftermarket multiple spark type ignition is usually good for a couple mpg. Also I have found the higher dollar spark plugs help too. I'm talking 5$ and up a piece. In my last 5 engine builds, all have received performance street cams and aluminum intakes, and all have done better than stock in the mpg dept. The engine doesn't have to work as hard to pull that heavy mass around. Also, I'm still waiting for my neighbor to put some mileage on it, but I recently installed a hydrogen gas system on his '97 Lexus SUV. He had been getting 13/14 mpg every day in town. I'll make a post about the outcome when he brings me some numbers in 1000 miles or so. We're hoping for around 19mpg.

[69GMCLonghorn]

Originally Posted by UltraBlue71

Q-Jet x4

He should put 4 Quadrajets on it?? Isn't that a little overkill for a small block??

[69GMCLonghorn]

Originally Posted by Myself

An aftermarket multiple spark type ignition is usually good for a couple mpg. Also I have found the higher dollar spark plugs help too. I'm talking 5$ and up a piece. In my last 5 engine builds, all have received performance street cams and aluminum intakes, and all have done better than stock in the mpg dept. The engine doesn't have to work as hard to pull that heavy mass around. Also, I'm still waiting for my neighbor to put some mileage on it, but I recently installed a hydrogen gas system on his '97 Lexus SUV. He had been getting 13/14 mpg every day in town. I'll make a post about the outcome when he brings me some numbers in 1000 miles or so. We're hoping for around 19mpg.

Guys, look at the lengths we go to in trying to squeeze an extra MPG or 2 out of these things. They are some of the greatest trucks made, but fuel misers they are not. Any of us could drop $10K into our truck (unless it's been done already) and STILL wouldn't get 20 MPG out of them!

Yet we all still kid ourselves and keep putting more perfume on the pig... And I include myself on that too. It's kind of like Homer Simpson grabbing the electrified donut. He gets shocked, and drops it. Sees it again, grabs it, gets shocked, drops it... and keeps doing it... Same thing. We can keep putting more perfume on the pig, but it's still going to shock us and drink the petrol like crazy... But they do look damn good doing it, don't they?!?!

[BB72CHEVKT]

Originally Posted by 69GMCLonghorn

Guys, look at the lengths we go to in trying to squeeze an extra MPG or 2 out of these things. They are some of the greatest trucks made, but fuel misers they are not. Any of us could drop $10K into our truck (unless it's been done already) and STILL wouldn't get 20 MPG out of them!

Yet we all still kid ourselves and keep putting more perfume on the pig... And I include myself on that too. It's kind of like Homer Simpson grabbing the electrified donut. He gets shocked, and drops it. Sees it again, grabs it, gets shocked, drops it... and keeps doing it... Same thing. We can keep putting more perfume on the pig, but it's still going to shock us and drink the petrol like crazy... But they do look damn good doing it, don't they?!?!

Look good and cheaper than a new one in the long run.

[chevy_mike]

Originally Posted by 67ChevyRedneck

Anyone getting 25-28mpg (in US measurement) with a TBI is completely full of crap. I don't know the converstion, but I know the Canadian gallon is bigger than the US gallon, even so, that seems high. 10-13mpg "city" is just about normal for ANY full size truck with a small block V-8 with just about any trans/rear end combo. The big difference is highway.

Not true. My parents '91 Firebird, with a 305, auto and TBI routinely got 28mph highway and the best they did on a long trip was 32mpg. This was cruise control set at 65mph on a long, flat streach of freeway.

Biggest advantage of the Firebird is that is was very aerodynamic, unlike our bricks (or most any) of a truck.

I had a program at one time that would tell you how much power it took, at what speed based on how much frontal area there was. It was amazing how much more power something like a truck took to push thru the air then a streamline car did. It was even more surprising as you went up in speed. Something like twice the speed took four times the power.

[69GMCLonghorn]

Originally Posted by chevy_mike

Not true. My parents '91 Firebird, with a 305, auto and TBI routinely got 28mph highway and the best they did on a long trip was 32mpg. This was cruise control set at 65mph on a long, flat streach of freeway.

Biggest advantage of the Firebird is that is was very aerodynamic, unlike our bricks (or most any) of a truck.

I had a program at one time that would tell you how much power it took, at what speed based on how much frontal area there was. It was amazing how much more power something like a truck took to push thru the air then a streamline car did. It was even more surprising as you went up in speed. Something like twice the speed took four times the power.

Well, hell, if we're going off the truck subject, my in-laws' '86 Tore-ass would get us 34 MPG with 4 people and luggage on the highway!