Oh, I ran the numbers on the block. 1968 327 but it's a (unknown) AxxxxxxA crate motor so I'm not sure if it has a 350 crank.

 

THE best mileage for SBC is the old Crossfire injection system from 1982-84.
Next would be an electric Q-jet setup w/700R4.

For what you have think BLOCK HEATER and use it faithfully. If you never cold-start and run on choke pumping cold oil with a daily driver your actual mile goes way up. You can also go with synthetic ATF in all the gear cases.

Have the front and rear ends checked for square with the frame, 'dog walking' scrubs off mileage.

Have fun with it.

 

the secret to good gas mileage has nothing at all to do with the engine...

but almost entirely to do with the loose nut behind the wheel...

that's right.. the DRIVER effects gas mileage a lot more then changes to the drivetrain will.

Intelligent driving, thinking ahead, planning your moves, holding the throttle steady as much as possible will do more to improve your mpgs than most anything else.

if you are the kind of driver that zooms up behind a slower vehicle.. stands on the brakes.. thinks about a lane change, then stands back on the throttle to make the pass, your mpg's are going to be a lot lower over all then someone who thinks ahead, and plans the lane change ahead of time and avoids having to slow down at all.

also, if you are a gas/brake/gas/brake/gas/brake kind of driver will hurt you a lot too.

or if you are like my sister who thinks the gas pedal has only two positions...all the way up. .and all the way down...

 

A good point was made on oil type which does actually make quite a bit of rolling resistance difference on synthetic from mineral based oil. On my last 71 Gm 4x4 I switched tranny (manual) transfer case and both diffs to synthetic iol and picked up 3mpg and that was in the winter months, shifted way better and rolled so easily, was actually surprised that it helped that much, the claims are true. also things like an advance curve kit for the distrib helps a bit and a rooler valve train, even rooler rockers alone help. It all ads up after a while. As you previously mentioned the optimal gear ratio also helps too.

 

Ya a friend of mine also mentioned the synthetic chassis lube. I already run Mobil 1 gold cap oil. I have the timing at 8 or 10 BTC initial and I think I did put a curve kit in the HEI. I noticed a huge power increase with the timing advance.

 

"if you are the kind of driver that zooms up behind a slower vehicle.. stands on the brakes.. thinks about a lane change, then stands back on the throttle to make the pass, your mpg's are going to be a lot lower over all" WOW that's exactly how I drive. Old habits are hard to break plus we have a stop light about every block in this town and they always seem to be red. I clocked a yellow to red light the other day at 2.5 seconds. That seems sudden to me. I used to have a 74 Caprice that had a 400 2bbl and that engine had a ton of torque...

 

SO anyway I have been driving it for a while. Performer intake and Q-jet made a noticeable difference in mileage. I changed to all synthetic fluids.
I also notice a small drip from the gas tank and I think it's been that way for about a year at least because of a trail I saw in the rain once. :spank: After I get a new gas tank I'll see what the mileage is like. Picture of finished truck...

http://www.hotrodders.com/gallery/showphoto.php/photo/64849/title/truk/cat/500

 

If you want to save gas join the community over at Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com they know how to save gas, they know it like a drag racer knows getting another tenth of a second out of his car. I use to spend a lot of time on that forum and learned a TON of stuff I never imagined before.


Brian

 

I find keeping the tires at 38psi does wonders for mpg.
The block heater is a good idea it cost pennies a day and save tons of fuel.. as it not stay on the choke, and you'll not have it idle'n warming up. it'll be start it and go..(after you unplug the heater) grease able u joints and a shot of grease every 6 weeks..
look at newer trucks there is a rubber filler between cab and bed.. to keep air going down side of truck makes a huge difference.
keep tailgate up, and no tono cover

A buddy put a belly pan under the full lenth of his reg cab 8 foot bed truck.. and picked up 5mpg !!!!!!!!just closing off the bed to bottom of bumper(if it has one) will stop the rear bumper from becoming a mini chute..

 

I find keeping the tires at 38psi does wonders for mpg.
The block heater is a good idea it cost pennies a day and save tons of fuel.. as it not stay on the choke, and you'll not have it idle'n warming up. it'll be start it and go..(after you unplug the heater) .

What!!
You're supposed to unplug it.
I forgot once!
My 100 foot cord was only 3 feet long after 5 miles.
I wondered what that noise was!! LOL!!

 

The brand of tires can make a HUGE difference! I was very surprised to see how much of a difference when I put new tires on my SHO. I had a few coasting spots where I would coast many blocks, and knew exactly how much I could go starting at a certain speed. I put new tires on it and it changed dramatically loosing a full block!

And driving style can make as big a difference as anything. In a study I did I lost 20% fuel economy driving aggressive, not crazy nut job aggressive, just aggressive like I use to before I got into hypermiling, like pushing stop lights and tailgating and driving 5 mph over the speedlimit. I gained 20 seconds on average to my location that was 5.5 miles away and lost 20% fuel economy!

Brian

 

The brand of tires can make a HUGE difference! I was very surprised to see how much of a difference when I put new tires on my SHO. I had a few coasting spots where I would coast many blocks, and knew exactly how much I could go starting at a certain speed. I put new tires on it and it changed dramatically loosing a full block!

And driving style can make as big a difference as anything. In a study I did I lost 20% fuel economy driving aggressive, not crazy nut job aggressive, just aggressive like I use to before I got into hypermiling, like pushing stop lights and tailgating and driving 5 mph over the speedlimit. I gained 20 seconds on average to my location that was 5.5 miles away and lost 20% fuel economy!

Brian

my '04 z71 got better mile per gallon at 75 than at 65, 85 was as good as the 65 speed limit.. steady 45mph was the sweet spot as it was just off idle and the 5.3 has enough oats down there to not lug when you get to an incline

 

I've been building high gas mileage vehicles for decades and I think there are a number of measures you can take before engine work that will return better mileage. WEIGHT is a major contributor to gas consumption. Imagine how much better mileage modern performance cars would get with out all the weight they now possess.A new Mustang weighs as much( really more) than a '69 428CJ Mach I. Everytime you leave a stop that weight is aggarvating the fuel consumption. Before I attempted to get more out of the engine I'd dump as much unneeded weight as possible.If you could lose 500lbs in a 3500 lb vehicle that would likely contribute as much to better mileage as engine changes. If you need 4 wheel drive look into manual lock out hubs and depending on the transfer case you might be able to get some internals that help as well. When it comes to engine mods, I'd focus on ignition and one of the newer self learning TBIs being offered by a number of companies. Electronic ignition and the FI addition will help to keep the state of tune to a higher degree.

 

I'm surprised you say your 90 EFI sucks gas. That would be if a 305 or 350 swirl port headed, throttle body injected engine with either a 5 speed manual or 700R4 automatic. This is a combination that should get pretty good mileage and certainly should do a quantum better at it than a 4x4 with Th350 auto and a 350 with a carb.

The 90 has most everything I would recommend you put on the 4x4, the reason is that's the combination that gets good mileage. Stating with the trans if a 700R4 it has a deep low for getting moving from a stop without having to push the throttle though the floor. It has an overdrive and lock up converter for dropping the revs at a freeway cruise for good mileage. This is a much better solution than Th350 and 2.56 gears. A carb just can't keep up over time with EFI. Carbs are just plain sloppy at metering and cannot make adjustments for wear of themselves nor the engine which the EFI does for itself.

For the most part what you can do with a carbed engine and a 3 speed automatic to improve mileage is so costly there is no reasonable payback period, especially with a 4x4.

Bogie

 

better mileage..

Not going to happen with a 4x4, best thing is synthetic lubes, and weight as mentioned, also that gear ratio is to much highway, would be better with around a 3.08 ratio. have to get the big heavy truck moving. Good luck you will need it with a 4x4.:thumbup:

 

Duct tape a raw egg under your gas pedal.
You'll be amazed at your new gas millage.

 

best advice ever!

 

gas milage

read your post have suggestion

if 350 has flat tops in it, or put 383 flat top stocker together, roller cam, gut port to gasket, put on propane, water inject, and hydrogen drip.
you wont even bother figuring out gas milage. my binder will go calgary to spokane $27.00 fuel

 

More Economy

Yes the first thing to do as we are having to do in the UK with a gallon of petrol at nearly £7, is to try and find a van with either a 1600cc or 2000cc engine!
Yes thats the aim when looking at economy.
We have recently been to our son's wedding in Manitoba, he has a 6.3 litre turbo diesel 4 door pickup 4x4 and complains about 16 miles to the gallon!
My first question is WHY?
His new wife has bought a 3.6litre Petrol 4x4 Hyundai, in our UK terms still far too big an engine although we understand they need 4x4 due to the poor wether conditions 8in Canada.
I've just bought a new car from Renault called a Captur, 1600 litre turbo diesel 2 wheel drive that does 57 miles to the gallon has an Eco feature to keep the mpg low, but is switchable to normal high speed running where it will do 35 mpg.
We have to pay a road tax in the UK based on the exhaust emissions, a guy who lives opposite ( has a big 4x4)has just renewed his road tax for another 12 months and pays £500!
We pay nothing because engine is so efficient, the carbon emissions are next to nothing.
I know a big shop truck looks good but there's got to be a compromise somehow towards using less fuel.

 

sadly we don't get the small turbo diesels here. hopefully the '15 chevy small truck with mini duramax will be a big hit.. and g.m. will see fit to install them in full sized reg cab 2wd trucks (work trucks) as these will be ideal.. and not(hopefully) the 50-60k that full sized diesels cost today

 

i drive a 98 toyota tacoma 4x4 4cyl. it gets me an honest 26 mpg highway .we pay 6.14 a gal. or 1.30 a litre.gave up on full size trucks long ago.not much need for full size unless you are hauling heavy trailers or plowing.most of the time all the shop truck caries cases of oil ,engine ,tranny ,rear end,etc.i put one extra leaf in rear springs,handles any thing iwant to put on back. im sorry,but it's hard to feel sorry for you guys who pay2.75 a gal.

 

i drive a 98 toyota tacoma 4x4 4cyl. it gets me an honest 26 mpg highway .we pay 6.14 a gal. or 1.30 a litre.gave up on full size trucks long ago.not much need for full size unless you are hauling heavy trailers or plowing.most of the time all the shop truck caries cases of oil ,engine ,tranny ,rear end,etc.i put one extra leaf in rear springs,handles any thing iwant to put on back. im sorry,but it's hard to feel sorry for you guys who pay2.75 a gal.

As far as the feeling bad.. your fuel cost is mostly taxes to have that government health care.. among other things.. your pump cost goes to more than just the fuel.. something we will face soon if someone doesn't give the ACA the axe

 

Move your bussiness over here, we pay $1.50 for a galon of 82 octane, $2.18 for 92 and $1.00 for a galon of diesel.

And it never snows over here...

 

i posted gas prices just to show the big difference in cost of gas .i did not intend to bring politics into the pitcure .if i want to talk politics i wouldn't go to hot rodders forum.

 

Politics...???

Who's talking politics...???

I'm telling what fuel cost here and that has nothing to do with politics.

 

i'm sorry , my comment was reguarding gearheadlife's comments.i'm not very good at forums yet,bit of a ******* with computers.

 

I have a 49 international KB5 school bus converted to a motor home. Loaded weight is about 12,000 lbs. With the original flathead 6 I got about 7-8mpg. (I use a motor record book in all my vehicles to keep track of repairs and fuel mileage.) I replaced the 6 with a Perkins 345-6 ci diesel. Perkins is a relative low compression engine, of about 16:1 compression. Using a slightly higher rear end and a 5 speed OD, my long term mileage was between 14 and 15mpg. With the mileage I put on it, fuel savings more than paid for the conversion. If I was doing it again, I would use a Dodge Cummins engine. Cost would be more, but performance would be much better. Anyway, I suggest you convert to a late model diesel engine.

 

That's exactly the way I would do it, I'll go for a 6.5 turbo diesel that fits your truck like a glove with almost no mods at all, you'll love it.

I did a diesel transplant long time ago into my brother's C1500, I used a Isuzu 4BD1 4 cylinder turbo diesel engine from a commercial truck, I mated it with an adapter to a 700R4 tranny, it was awsome, not very powerful but more than enough, if I had to do it again, I would of used a lower rear end ratio, probably like 2.73 or 3.0

we have here toyota, mazda and Isuzu small pickups with 2.5 to 3.0 litre diesel engines, they perform awsome, and they are faster than the gasoline 4 cylinder models, not to mention that with fuel at $1.00 per galon they can't be cheaper to operate.

 

And on the brake pedal! Think about it, if you could drive your car from one place to another without ever touching the gas or brake it would get fabulous milage right?

Basic rule, if you are hitting you brake pedal and you aren't STOPPING, you are traveling too close to the car in front of you. I love to sit back a number of car lengths and the car in front of me is one length away from the car in front of him and the brake lights are flashing over and over and over like the darn 4way flashers are on! LOL

When the car in front of me hits his brakes (really hits them) I simply let off on my gas. Before I even have to hit the brake he has moved back up to speed and I just stop coasting and hit the gas again. If you aren't stopping you don't need to hit your brake.

Brian

 

Ahhh Brian
Life in the larger cities.

I have a commute, all but 2 miles is hiway.
in this 30 miles
1 stop sign
5 signals----includes the offramp signal (only 2 signals 2 years ago)

Nothing annoys me more than 2 people driving side by side and taking 1/2 mile or better to get up to 50 mph.
Not saying I am a "Jackrabbit" starter, but I want the cruise set as quickly as possible.

Now my computer controlled k1500 and the Ranger can accellerate quite effectively using the resume feature of the cruise-----pretty sure the engineers that designed this took fuel consumption into consideration
when creating this feature. Pretty sure after shifting into 5th at 45, and hitting resume is lugging, but even with that I (if I can get by) pass these
guys like they are going backwards.

No point in "gently" accellerating and using a mile to get up to speed.
Any acceleration means a drop in vacuum, retarded timing, and a load on the engine.
Dragging that load out, and you are just lugging, and quite possibly be using more fuel that if you just "got it up there".
Ever get behind a guy that merges onto the freeway at 40--then takes another 2 miles to get up to speed??? He is SUPPOSED to be at speed
when he merges.

Naturally---geograpy and population will have a bearing on how one drives or what he goes thru. My commute is nothing like yours, so driving habits are a bit different.

Hyper milers----Bah

(rant over)

 

The first thing you have to do is accept the fact that there are others on the road who are just like you, they are going to work, a doctors appointment, what ever, they are just going somewhere, they aren't there to be mean to Bryan.

Accept the fact that this person is in your way for seconds, friggin seconds not minutes or hours, seconds. Just roll with it and enjoy life.

Brian