Way to improve fuel economy??

[odog]

So yesterday I went to the hills again toget a load of wood. I put the gps in the truck cause I wanted to get a good estimate on my fuel mileage. I put 184 miles on the truck, not freeway, but back country roads, up and down in the mountains, I bet 40% was in 3rd gear at about 30 mph.

Here is the deal, I have a 327 with upwards of 170000 miles on it, a sm420/221 combo, 4:10 gears. It is a 3/4ton 4x4. Single exhaust aslo. The motor has good compression, 2 cyclinders have 150lbs and the others range 145 down to 130lbs. I run a quart of lucas oil every oil change, dont know if this helps or not, it may just be mental for me.

On this trip I got 9.3 mpg. Not great, but what gets me is last year I had 3:07 gears and got 9.7 mpg on the same trip, going almost exactly the same places.

Does anybody have any ideas for better gas milage? I mean at 9 mpg I could almost justify putting int he 396 I have and have more power. I havnt done it cause I didnt want to drastically change my milage, but I am wondering if it matters at this point.

[SactoJim]

By today's standards, bad mileage, but given an old heavy 4x4 with aggressive gearing and a good old fashioned carbed small block.....that mileage probably isn't too bad. Headers and duals would help some and you didn't mention what carb you had, but a small (600cfm) spreadbore type would probably be best. Fuel injection would be of some benefit, but by the time you figure the cost of that, you're probably best off to do a late model 5.3 swap.

[cdowns]

get your wood delivered you'll get better mileage

[biggestjohn]

It takes torque to get a load moving, a 327 is not a good torque motor. Low speed, starting and stopping, hills, all hurt mileage. The reason that all stated fuel mileage estimates are much lower for city driving is because it takes so much energy to get the load moving, but once its at speed, it doesn't take so much.

Its all a compromise, if you did build a motor that got good mileage, it would suck at hauling, if you build for hauling, it will suck for mileage.

Yes, you can put a diesel in it, put in an overdrive transmission, which has a better first gear ratio, fuel injection........but the cost will eat up your savings.

BTW:a lower first gear ratio helps very little if your not in overdrive, and if you put the 3:07 gear back in, the engine will lug in overdrive, and you will gain nothing.

You could buy a newer truck, but there again how long do you have to drive it before you actually start saving money.

Or you can accelerate VERY SLOWLY, which takes forever, (at least for people as impatient as myself ) and watch very carefully that you don't try to accelerate while going up hill. (of coarse, most cities built the intersections as the low point for drainage, so your almost always accelerating up hill)

[odog]

Originally Posted by biggestjohn

It takes torque to get a load moving, a 327 is not a good torque motor. Low speed, starting and stopping, hills, all hurt mileage. The reason that all stated fuel mileage estimates are much lower for city driving is because it takes so much energy to get the load moving, but once its at speed, it doesn't take so much.

Its all a compromise, if you did build a motor that got good mileage, it would suck at hauling, if you build for hauling, it will suck for mileage.

Yes, you can put a diesel in it, put in an overdrive transmission, which has a better first gear ratio, fuel injection........but the cost will eat up your savings.

BTW:a lower first gear ratio helps very little if your not in overdrive, and if you put the 3:07 gear back in, the engine will lug in overdrive, and you will gain nothing.

You could buy a newer truck, but there again how long do you have to drive it before you actually start saving money.

Or you can accelerate VERY SLOWLY, which takes forever, (at least for people as impatient as myself ) and watch very carefully that you don't try to accelerate while going up hill. (of coarse, most cities built the intersections as the low point for drainage, so your almost always accelerating up hill)

A diesel isnt an option, not really into diesels in these trucks. The truck is my DD, but I go 6 blocks to work, and 6 blocks home. Usually just use the truck for hauling or taking my girls fishing.

I figured that the milage is just what it is, like you said SactoJim, its old heavy and 4x4 so it isnt an econobox, I just didnt know if there was anything I could do to boost the milage a little. I am thinking getting rid of the points ignition and upgrading to HEI, I think that may help a little. The carb is the stock Q- JET, I have an edlebrock 600 that I should put on. I also need to dual exhaust it, just need to figure out best routing for the pipe along the tcase. I would like to eventually go with the 396/nv4500, but not right now. Which is better, 396 or 454 for torque. I have a 396 is the only reason I am thinking along that line.

Hauling 5600 lbs of wood hurts the milage a bunch, but it also gives me heat in the winter and the extra is a little cash in the pocket.

Im just fishing for ideas I guess.

[74 shortbed 406]

It's a 3/4t. How much are you willing to spend to get a couple extra mpgs, being a 4x4 its not gonna get much better than 12 -14 mpgs being 3/4t also. A 327 is a great motor. But it doesn't fit the situation.

[biggestjohn]

6 blocks?! That not even enough time to get the engine warmed up. I doubt that the choke has even opened up completely by the time you arrive to work.

[jocko]

I would submit that any drive that includes going up and down hills and 3rd gear only 40% of the time is not only going to be low (and that's ok, it's expected to be low in that scenario), but it's also going to be difficult to compare to something else just because you're constantly on/off the gas, up/down hills, etc. It is a data point, but not a real useful one.

I would say that if you want to compare configurations - the only apples to apples comparo will be highway mileage. Preferably interstate-non-stop at reasonable speed.

Of course it will be higher mpg because it's highway, but at least then, the only variable is the changes you make to the truck, not the possum you dodged (or accelerated to hit) in the hills on the first trip and not on the 2nd trip.

Considering your configuration, especially the rear gear, 9.anything is very respectable.

Don't get me wrong, I do understand your question is - what to do to get BETTER mileage, regardless of what it is now.

So, I'd ask this -

1. do you "need" a 4.10 rear gear?
2. If you have 170k on the truck, what shape is the trans in? i.e. if it COULD be construed that it's time for a rebuild (or if you can convince yourself of it in order to justify the idea) then, you could do the following:

700R4 and 3.73. That will help you a lot. Perhaps 3.55 or 2.42 or 3.23.

NOW, it sounds like you USE the truck, and that is awesome - so, you may actually need the 4.10 and you may like a manual trans... so, if either is the case, then I think you're stuck with 9 mpg, and that's really ok if you like the truck's perf as is - 9.X is really good for a 4.10 rear 3/4 ton truck I think.

While EFI could help - you'd probably have to drive for about 50 yhears to recoup the investment in gas savings.

[odog]

Originally Posted by jocko

So, I'd ask this -

1. do you "need" a 4.10 rear gear?
2. If you have 170k on the truck, what shape is the trans in? i.e. if it COULD be construed that it's time for a rebuild (or if you can convince yourself of it in order to justify the idea) then, you could do the following:

700R4 and 3.73. That will help you a lot. Perhaps 3.55 or 2.42 or 3.23.

NOW, it sounds like you USE the truck, and that is awesome - so, you may actually need the 4.10 and you may like a manual trans... so, if either is the case, then I think you're stuck with 9 mpg, and that's really ok if you like the truck's perf as is - 9.X is really good for a 4.10 rear 3/4 ton truck I think.

While EFI could help - you'd probably have to drive for about 50 yhears to recoup the investment in gas savings.

Actually I just tore the trans down this winter and put new bearings, seals and an output shaft in, the shaft was wore out and since I was in there, I thought it would be dumb not to do the bearings and seals.

I like the 4:10's but I am not married to them, I swapped out the front and rear axles because the 12 bolt was a little week for hauling and thats the gearset they came with.

I love electronics, just not in my vehicles. I like the simplicity of my truck, I like being able to work on it and I guess EFI kindof scares me. And I agree it would take forever to reap the benefits of it in fuel milage.

I guess it sounds like I am shooting down all the ideas I am getting, and that is not my intent. Truth is, I dont know what I am after, I guess it just bugged me that I only went 184 miles and had to fill up again to make it home. Feels like my range is limited. I could have spent all weekend driving in the hills, cutting wood and dinking around, but I had to come back to civilization to get fuel.

Thank you for the suggestions, I appreciate all the good info you guys give.

Erik

[GASoline71]

It's just a fact of life that these rigs were built when gas was way cheaper. We didn't care that rigs got crappy gas mileage back then. A high mileage SBC in a 3/4 ton in the woods is always gonna get crappy gas mileage... period. Even changing the gears and switching to EFI isn't going to be that big of a change. On the highway... sure you'll see a difference. But luggin' a big 3/4 ton 4X4 in the woods is always gonna suck fuel.

Gary

[3ought2]

Originally Posted by odog

I could have spent all weekend driving in the hills, cutting wood and dinking around, but I had to come back to civilization to get fuel.


Erik

Wont improve fuel mileage, but two five gallon cans of gas may buy you some 'dinking' time.

[jocko]

aux tank maybe? No worries odog, I do know how ya feel. My 66 gets maybe 11 mpg on a good day (stock 283 in it with a 4 bbl), and I spent a whole summer and more than a few bucks sticking the T5 in it... I shudder to think what my mileage was before.... (i have 3.73s in back)

[odog]

Originally Posted by jocko

aux tank maybe?

Originally Posted by 3ought2

Wont improve fuel mileage, but two five gallon cans of gas may buy you some 'dinking' time.

Originally Posted by GASoline71

It's just a fact of life that these rigs were built when gas was way cheaper. We didn't care that rigs got crappy gas mileage back then. A high mileage SBC in a 3/4 ton in the woods is always gonna get crappy gas mileage... period. Even changing the gears and switching to EFI isn't going to be that big of a change. On the highway... sure you'll see a difference. But luggin' a big 3/4 ton 4X4 in the woods is always gonna suck fuel.

Gary

I have toyed with the idea of an extra tank. I have room behind the back axle under the flatbed for a blazer style tank, maybe I should do some measuring and see what I can come up with. Even packing 2 five gallon gas cans is a good idea. I can strap them down, fill up the truck when I am loading wood, and throw them on top when they are empty.

You are right, a heavy truck up and down in the woods isnt good on fuel, just something I need to live with.

Thanks guys

Erik

[GASoline71]

Erik... I'm in the same boat... I don't own a single vehicle that gets better than 12 MPG...

Gary

[MrSchaeferPants]

Nothing worth while. Anything you do will take you years and years to recoup the funds. And THEN you start saving. Make sure its all running 100%, that's all ya can do.
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[special-K]

If it ain't broke,don't fix it. A .4 difference in MPG,especially on such a run,is nil. That could be the difference in atmospheric conditions that day,like barometric pressure/temp. Sounds like you have a good combination. What's all this poo-poo about the 327 not being the right motor,not making enough torque??? Hog wash. It was the biggest engine offered until 1968 and these trucks did everything the world asked them to...probably longer than any other made...and earned a great reputation which lead to the reason all you guys want them 40 years later. They're no just a pretty face. Hauling a load of firewood over hill and dale,back roads mostly in 3rd gear and getting 9+ MPG is doing good.

[leftybass209]

A well worn SBC pulling a load up and down hills exhaling through a straw can't be good for gas mileage! I would like to think 9 mpgs would be acceptable given all the stats you have given. I know you suggested a big block not being a bad alternative at this point, but a rebuilt mild SBC will always beat out a rebuilt mild BBC for gas mileage. Given a real high mileage BBC with your conditions you could be looking at possibly 7 mpg. That's what the 70s c10 I had was getting before it died out.
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[biggestjohn]

Originally Posted by odog

Actually I just tore the trans down this winter and put new bearings, seals and an output shaft in, the shaft was wore out and since I was in there, I thought it would be dumb not to do the bearings and seals.

I like the 4:10's but I am not married to them, I swapped out the front and rear axles because the 12 bolt was a little week for hauling and thats the gearset they came with.

I love electronics, just not in my vehicles. I like the simplicity of my truck, I like being able to work on it and I guess EFI kindof scares me. And I agree it would take forever to reap the benefits of it in fuel milage.

I guess it sounds like I am shooting down all the ideas I am getting, and that is not my intent. Truth is, I dont know what I am after, I guess it just bugged me that I only went 184 miles and had to fill up again to make it home. Feels like my range is limited. I could have spent all weekend driving in the hills, cutting wood and dinking around, but I had to come back to civilization to get fuel.

Thank you for the suggestions, I appreciate all the good info you guys give.

Erik

carry a gas can.

[ole dollor]

odog:get a bigger truck....so you can haul more wood, you wont have to go as often.....lol

[odog]

Originally Posted by ole dollor

odog:get a bigger truck....so you can haul more wood, you wont have to go as often.....lol

I am looking for a 2 1/2 ton truck. I have seen a few around here, but they are in pretty bad shape machanically. I found 1 ford that looks to be in good shape, but I can never seem to catch the guy, It has a dump bed and everything.

For now I will just keep on using what I have, shes reliable and I know her issues. I can get 2 cord of wood on her and thats a decent day of cutting.

[ole dollor]

dump bed would be nice unloading .....good luck....

[swissarmychainsaw]

I have a pickup with a 20 gal tank which I feel like I fill it up every time I get into it.

I have a suburban with a 40 Gallon tank which lasts me a week.
It stings a little to put $100 worth of gas in at a time, but I LOVE having the range.

Go the bigger tank route, it's likely the cheapest option.

I also have a mount for a Jerry can, which is the "no brainer" way to expand your fuel.
Though you will easily be into $100 per can mounted.

My PO put one of these in the burb:

[Hawghauler]

For best mileage, the Rochester is the best carb. Get it rebuilt if it's tired. A big block will make a small difference in mileage, but quite a bit in grunt. An OD trans will help long term, and your gears are right for it, but it won't pay for itself so only do it if you take long trips regularly. Headers will help both mileage and torque, along with the dual exhaust of coarse, but don't expect any miracles.

[special-K]

Yeah,I'd run headers & duals,go head with a GM HEI,nice Q-Jet,big air cleaner,all tuned up

[Matt Cramer]

A bit of a tune-up may help, and possibly even some rejetting the carb depending on where your air/fuel ratios are now. Also, do you have a vacuum advance hooked up on the distributor? I've seen those unhooked, and that will hurt mileage significantly.