Need ideas on a SWB build

[clemdaddy]

I am beginning a new build on a 66 SWB. The main focus is mpg. With gas hitting $3 again I have decided that this truck should be an attempt to get great mileage and still retain a certain amount of the cool factor.

What I have is a bare frame, good sheetmetal, several 283 and 327 engines, a vortec 4.3 and t-5, a 700r and turbo 350. also there is a backyard full of 64-66 trucks for parts... plus a big willingness to do whatever is necessary to reach a goal of 25-30 mpg. (if possible)

Since this build is just beginning I am willing to modify anything with the one criteria of maintaining some sort of an original look.

I would appreciate any and all sincere suggestions. Treat it as if it was your truck and tell me what you would do.

Thanks

[jonzcustomshop]

there is a guy in great falls mt, that converted his s10 to electric, it sits real low because of all the battery weight.
I would love to do that to a 60-66, could even use the power glide, he said his range is about 70-90 miles...

in your case,
283 2bbl would probably be a good choice for mileage, a higher rearend ratio, and the od auto would probably help too.

[duallyjams]

The lower the truck the better for reducing drag. Skinny tires will also help in reducing drag.Make the truck as light as possible ie light weight wheels & brakes even a light weight drive shaft. Definitely a OD trans just depends on your driving stile as to a auto or stick but a stick is alot more fun.I have read other threads with people using 5.0 with the OD trans in 67-72 getting 22-25 mpg.

[markeb01]

I would think a 283 or 327 with a mileage cam, electronic ignition, lean carburetion or fuel injection, free flowing air filtration and either a 5 speed manual or overdrive automatic would produce good results. Then it’s on to little things like a flex or clutch fan, fine tuning the best ignition curve in the distributor, etc. Establishing the preferred driving speed will help in selecting tire diameter and rear axle ratio, which will be critical. The engine must produce good torque in the rpm range where it will spend most of its time. If the rear axle ratio is too high, the engine will bog and cost mileage. Driving at 55 rather than 75 will also help the goal, as these trucks are not lightweights, and are about as aerodynamic as a parachute with the large flat frontal area and built in air brake above the windshield.

[pmkrew]

I think it would be obtainable. I would go with the 283 and 5 speed manual od trans for mileage. Personal preference would be a good mild camshaft, a good flowing set of small chamber aluminum cylinder heads(maybe 90's vette) , fuel injection and a turbocharger to add little help with hp.

My first truck was a 66lwb stepside 283 bored to 292 and comp cams magnum cam, 550 cfm holley 4barrel, edelbrock torker2 intake, 4.10 gears, 255/60/15 tires and a 3spd column shifter and when I drove it sensibly I achieved around 16mpg intown driving.

If I only still had that truck today...
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[clemdaddy]

good ideas... and the drivetrain will happen soon. sorry I wasn't clear about it but what I'm looking at right now is the frame and suspension.
duallyjams mentioned light weight and lower ride height, this is the start.

how to shave pounds?
dropped spindles and disc brakes ok...maybe tubular control arms got to be lighter than original. dropped springs or coilovers for reduced drag. aluminum driveshaft...
what else could be done to the suspension and frame if the goal was to shave a couple of hundred pounds?
and would 3:55 gears be a good starting place?
and does a posi spool help or hurt mileage?

Thanks...

[pmkrew]

Cutting weight, tubular control arms, lighter springs, disc brakes, reasonable tires, aluminum wheels could all be lighter. The narrower the tire the less rolling resistance. Rear gear ratio is going to be dependent on hp, tire size and transmission choices. Depending on how this truck will be driven you could get away with a higher ratio if it's mainly going to see short trips, if highway driving is a concern anywhere from a 3.23-3.55 I have found to be decent. The posi-trac rears will have little effect on mileage, stay away from spools/ mini spools for on road usage, they'll make slow maneuvering more challenging...
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[TwoFiftyShifter]

That 4.3l has a lot of mileage potential, my friends s10 has it with the 5 speed and 3.42 gears, extended cab 2wd probably similar weight to your truck but more aerodynamic, he shifts early and gets 18-20 in town and 22-24 highway.

[astrochimp]

Greatest results in weight reduction in this order-

1st things that move at engine speed. (pistons)

2nd things that move at wheel speed (wheels/tires)

3rd dead weight (body)

Saving 10 lbs on wheels & tires helps more than 10 lbs of body.
Tires and wheels are something very easy to watch the weight on, & tires can very 5-10 lbs in the same size from brand to brand.

An aluminum drive shaft 'MAY' help, but many weight effectively the same as a steel one.
Light weigh a arms will not be cost effective at reducing mpg

Once you pick gears and tire size you can build engine to work at that RPM (don't buy a huge cam and high rise to run 2200 rpm!)

Low reving larger cid engines that have lots of low rpm torque have been best for me, but if your 4.3 has the injection and pcm, it might be the way to go.

[N2TRUX]

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[N2TRUX]

No matter motor you use an injection system will help mileage. The 4.3 is great for mpg and tq but may suffer on your truck due to weight. Even better would be a 5.3LS motor.
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[Allensracing]

cummins turbo diesel. power and fuel economy. about the same size and weight as a 454.
25 mpg is easy, and you could have more power than you need

[lakeroadster]

Originally Posted by N2TRUX

No matter motor you use an injection system will help mileage. The 4.3 is great for mpg and tq but may suffer on your truck due to weight. Even better would be a 5.3LS motor.
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Excellent point. Fuel Injection is a must if your goal is maximum mpg per cu-in.

Take a look at HP vs. gas mileage of the carb'd vehicles of the 60's and 70's vs. today's HP vs. gas mileages.

That being said if your goal is to keep track of all expenses during the build and then end up recouping your expenditures due to gas costs, the most cost effective approach is for you to buy a finished or nearly finished 60-66 truck and save all the money you would have spent on higher dollar components to reach your great gas mileage goal. Then use that bundle of cash you saved to buy fuel.

If your goal is to build a great mileage truck "because its what you want to do, not in order to save money on the truck build", then dig and have at it.

Either way, have fun with it and keep us in the loop.

It's kind of like buying a Prius vs. Camry... or a Volt vs. a Malibu. Take the dollar savings and put it toward gas costs... you'll be ahead in the long run. Of course this comparison won't be valid when we run out of fossil fuels...... that won't be happening anytime soon though.

[Rich 5150 69]

Vortec 305 with a 2004r, have a friend with one in his `66 sb, with 350 gears his final ratio is about 308 he gets 24 highway, low speed driving is great due to the low end torgue of the vortec and it is carburated with a quadrajet.

[duallyjams]

I had a 2.8 v6 s10 and got 26 to 32 mpg. I currently a D-MAX allison in a crw cab dual rear wheel and get 22mpg. I also have a 64 gmc 305v6 with 2 barrel holly that gets 7mpg. So yes you can get good mpg in a older truck with modern tech.

[Allensracing]

I have a 66 chevy sb with a stock 454, holley 850 double pumper, th350 trans that gets 15 mpg hauling my motorcycle on the highway at 70 mph.
I plan to make a few changes. I would like to get 20 mpg out of the combo

[TwoFiftyShifter]

15mpg is the best I've heard from a 454. Must have a tall rear end gear

[Allensracing]

very steep gear. the converter doesnt really lock up until about 65 mph, i need to change to a tighter converter.
lowering the truck helped a lot too, as did removing weight.
I built a chevelle for my mom, it gets about the same mileage from a 377 with a 540 lift cam and an 850 holley and 3.08 gears. she has been daily driving the combo for about 6 years now.
I am more into performance than economy, but certain things can be done to acheive a little of both

[old cruiser]

I don't know what its like over there but down here in Oz for reducing fuel costs most convert to LPG which is 62 cents per litre as apposed to $1.29 per litre of petrol or $1.35 for premium petrol. For me fuel is what we need to buy to enjoy driving so the cost is niether here nor there.

[clemdaddy]

Appreciate everyones opinion, we all got them.
I wanted to add a few pics of the truck to give an idea of where it is in the build. And answer some questions...
lakeroadster, my goal is to build a great mileage truck. with hopefully well informed and thought-out decisions along the way. I don't mind a few mistakes and redos as long as they weren't the really expensive ones, that's where you guys can help out... and what makes this place great.
pmkrew, i'm thinking that 3:55 gears, 2v throttle body 283, 5-speed manual would be a good start. i've had some success with the aftermarket holley pro-jection before and get it as far as tuning.

the pics... firewall, PO had a unique way of installing hei. rockers, floor mounts and kick panels were toast and will be replaced. left side door support and air vent tunnel were crashed into and will be replaced.
rear cab shows both cab corners need replacement.
frame is solid, a couple of crossmembers get changed and those big wheels and tires got to go. well thats the start. the cab is getting more time now because the frame is outside in the brutal cold.
Thanks for the input and i will update and check in often.
Clem

[Clyde65]

I have the 4.8\4l60e FI in my 65 with 3.08 rear gears, currently I am getting 14 or so in the city, I get over 20 highway and when I get the tune redone, that should improve about 10-20% from what I'm told.

[sailed2japan]

Here's my train of thought for how I would do this build:
Chassis:
3" drop spindles, 3" rear drop springs

Engine:
optimized for low end torque. Maybe even use a straight 6, but I don't know what's out there for performance on them. Skip the projection too much money for me.

Trans:
STANDARD with od. To me putting an auto in a vehicle you want good mpg out of is like going on a bacon diet. It makes some things easier, but it makes your goal a whole lot harder.

Tires & Rear Gear:
Once you've got all that togetherI'd put on a pair of 235 or 245 width tires in the highest height you can get good clearence with, but this is where the tricky stuff starts. You'll need to balance where your peak is for torque vs. fuel consumption. Obviously you want the most torque to push yoou down the road with the least amount of fuel. I'd also run the highest load range tire you can find in whichever size you choose. Yes, they are heavier, but the side walls are stiffer, which means lower rolling resistance. I had real good luck with Michellin LTX's in the past, they last a LONG time, too.

Body:
They say Toneau covers help, I don't know how much, but I do like the look of the old soft style and keeping things in my bed out of sight and the weather. I'd also try to make some sort of air dam for under the front bumper. Any air that gets under a vehicle is just trapped there causing drag.

And what may be the silliest of all...............mirrors

Now I haven't done any testing on this, but in theory it sounds resonable. I seen quite a bit of discussion about how mirrors can cost you milage on the highway. the reason for this is that with all the air pressure built up on the windsheild as it rolls around the side of the truck it has a much greater effect than if the mirrors where in a clean air stream. In my mind this would have an even great effect on our trucks as they don't allow air up over the roof so well.

Hope this gives you some food for thought.

[Allensracing]

I have tried twisting my mirrors sideways on a few boring long trips, it did not have a noticeable affect. lowering the truck had a dramatic affect

[kieth]

What type of driving do you do?

If it is on highway then a 350 tbi or vortec with a OD transmission and 3:08 gears would be great.......set it up to cruise low rpms at the speed you want to cruise at.

skinny tires and wheels, lowered, on the lowering front look at airbagit, I put air springs on my 66 gmc for 220.00 lets me control the altitude of the rear end and it rides great does not cost much more than spring.

If it is going to be a in town truck they you must stay with a smaller engine. If it is city driving you will never get it to that high a mpg number.

I thought about doing the same thing and would look at using the 4 cyclinder engine out of a chevy Equinox 32mpg highw fwd with 6 speed auto......the chevy equinox actually weighs more than the pickup. it might work....and still have acceptable power...........look at the 4wd version Kieth

[sailed2japan]

That reminds me of an idea I had a while ago about using an inline 6 from a trailbazer or envoy. they don't get great mialge in those SUV's, but you be a little lighter, plus you can pull off all the EPA crap that chokes up the motor. Then you'd have multi point injection to boot! I wounder if there'd be a way to hook it to a stick, though.....