How Many Miles Per Tank?

[armybyrd]

Ive got a '83 stepside thats 2wd and has a 305 engine and 350 trans.
Im barely getting 200 miles per tank. I realize these trucks arent that efficient but is this average or is something wrong with my setup? Everythings stock besides an Edelbrock carb btw.

[armybyrd]

Also how much would a 700r4 help gas mileage?

[86c20]

in my c20 i get 200 to the last 1/4 of the tank that is not highway. highway is more closer to 250. that is with 18 gall tank at speed

[J Knight]

If you got a 16 gallon(14 useable) tank at 15mpg, that will only get you 210 miles. An OD tranny might get you to 18 mpg if your keep your foot out of it.

[wilkin250r]

200 miles sounds about right, actually, if you've got the smaller tank. I've got dual 20 gallon tanks, I can drive 600 miles. But it costs me about $150 to fill up!!!

[INSIDIOUS '86]

About ten miles per tank. All sideways haha
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[GM-power]

I never took the time to figure my mpg (kinda scared). 200 miles sounds like a good number. Me and my 357 probably don't get that.
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[Axle]

Sounds about right for ethanol spoiled fuel. My injected vehicle doesn't care what goes in the tank, but the carb'd vehicles have a very noticable drop in mileage per tank when using a 10% blend.

Alex.

[ont_guy_38]

Yup that's about right. I probably only get half that .

[dieseldawg142]

my crew can manage about 220-240 miles on a fill up (dual 20 gal. tanks). a little less around town. 454, t400

[Firebirdjones]

Originally Posted by dieseldawg142

my crew can manage about 220-240 miles on a fill up (dual 20 gal. tanks). a little less around town. 454, t400

Yikes, I hope you didn't mean you are filling both of those tanks to go just 220-240 miles...

My 79 454/400 turbo has dual 20 gal tanks. I go 200 miles on one tank before switching and still have 1/4 tank left in it before I switch.

Accross country I could stretch it and average about 450-470 miles before a fillup and still leave just under a 1/4 tank in each one.

Around town driving is less obviously, but I can still fill both tanks and go for 2 weeks without a fillup around town averaging about 350 miles and using 30 gallons (again switching the tank at about 1/4 tank left).

Armbyrd, if your speedo is correct, fillup and keep track of mileage, and fillup again recording the gallons. That will tell you the exact mpg you are getting. 200 miles per 20 gallon tank is in the ballpark, but how far towards empty are you going, or more importantly how much do you have to put back in at fillup time?

[C-10 simplex]

Not good. i get about 294-302 per tank.

As far as the 700r, it depends on what your rear axle ratio is.

i think the only way to get over 20 in trucks like these are, in order or preference:

1) move down on cubes----4.3 v-6. This may reduce towing/hauling ability.

2) 6.2 diesel

3) A new LS with cylinder deactivation. A regular LS should do it too.

[Firebirdjones]

Originally Posted by C-10 simplex

Not good. i get about 294-302 per tank.

As far as the 700r, it depends on what your rear axle ratio is.

i think the only way to get over 20 in trucks like these are, in order or preference:

1) move down on cubes----4.3 v-6. This may reduce towing/hauling ability.

2) 6.2 diesel

3) A new LS with cylinder deactivation. A regular LS should do it too.

I've done it with carbed 350's, (over 20 mpg) with an overdrive and sharply tuned. So it's doable but most people won't or can't spend the time to dial one in properly. Shucks I get 17 mpg out of my 70 formula with a 434 cubed pontiac, a carb, 400 turbo, and 3.31 gears. An overdrive in that would put it right at 20 mpg piece of cake.

I get 22 mpg with the 6.0 LQ4 (LS engine basically) swapped into my 72 4x4 blazer, 4L60 and 3.73's on 33" tires, and no cylinder deactivation (that's cheating ). Alot of people told me mileage wasn't going to be it's strong suit either, but it holds it's own against any new V8 SUV. A 6.0 is just 364 cubes, it's not a big engine by any means.

There is so much more to mileage than the engine choice. It's really best to concentrate on the little things before spending money changing the total package. So many things that rob power and MPG. Tires, wheels, the weight of the tires and wheels, tread patterns, the tune, the weight of the vehicle, driveshaft, engine driven fans, oil viscosity, gas quality, correct gear choices, transmission choices. You can go on and on, and find at least 2-3 mpg if you are willing to spend the time and money on simple things first.

If I can get 14 mpg out of my 79 1 ton with a 502/400 turbo and 3.73's then anyone can at least do it with a 350. I'm expecting to pick up another 2-3 mpg with the gearvendor install.

[dieseldawg142]

Originally Posted by Firebirdjones

Yikes, I hope you didn't mean you are filling both of those tanks to go just 220-240 miles...

My 79 454/400 turbo has dual 20 gal tanks. I go 200 miles on one tank before switching and still have 1/4 tank left in it before I switch.

Accross country I could stretch it and average about 450-470 miles before a fillup and still leave just under a 1/4 tank in each one.

Around town driving is less obviously, but I can still fill both tanks and go for 2 weeks without a fillup around town averaging about 350 miles and using 30 gallons (again switching the tank at about 1/4 tank left).

Armbyrd, if your speedo is correct, fillup and keep track of mileage, and fillup again recording the gallons. That will tell you the exact mpg you are getting. 200 miles per 20 gallon tank is in the ballpark, but how far towards empty are you going, or more importantly how much do you have to put back in at fillup time?

i wish i could get 200 on one tank, but sadly that's my range on both tanks (full 40 gals., new tanks). my 38.5 swampers don't help, nor do the 4:56's behind a t400, then throw the camper & trailer on & i can barely crack 5mpg's, plus i live in bc, land of mountains- forget about feather throttle driving

[Firebirdjones]

Originally Posted by dieseldawg142

i wish i could get 200 on one tank, but sadly that's my range on both tanks (full 40 gals., new tanks). my 38.5 swampers don't help, nor do the 4:56's behind a t400, then throw the camper & trailer on & i can barely crack 5mpg's, plus i live in bc, land of mountains- forget about feather throttle driving

Yikes!

When I pulled the 28 ft. enclosed trailer loaded my mileage dropped from 14 (empty, truck only) to an average of 10 mpg accross country. It would dip as low as 9 mpg occasionally depending on the terrain. 10mpg was a big drop from it's normal 14 but the trailer weighed a good 10,000 lbs. too so it wasn't too bad for a gas powered BBC. Overall I'm pretty happy about mpg with this old pig.

But I'm running stock 9.5x16.5 tires (30" tall) and a 400 turbo with 3.73's. I keep rpm just under 3,000 (about 65ish) and it does pretty well.

[frog210]

my 74 with a 305 v8 and 350 get around 10-11mpg

[Rubble]

I just got the 82 back on the road about a month now:6.2/A833/208/3.73 on 35s 6" lift.It's been cool out,so it's pretty well running from when I leave in the morning til home around 4-5.Put between 80-100 miles a day on it and it's been 16-18 mpg.Once summer is back & very little idling should be close to 20
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[kalbert]

I don't know exactly but I'd guess 120 or so miles on a small tank, maybe less trying to keep up on the highway. I wish it were 200!
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[csdineley]

200 - 210 is what I get from a single tank as well. 1987 R20 350 TBI, th400, 4.10, dual 20 gal tanks.

[Number21]

That's right about where I'm at - 10mpg. I've tried and tried to get better but it just ain't happening.

[Skunksmash]

Originally Posted by armybyrd

Ive got a '83 stepside thats 2wd and has a 305 engine and 350 trans.
Im barely getting 200 miles per tank. I realize these trucks arent that efficient but is this average or is something wrong with my setup? Everythings stock besides an Edelbrock carb btw.

My 87 with a tbi 350 gets about 205 miles per tank. I hear that's bad. Its about 14 MPG and other people say the same truck gets 17 to 20.

I used to have a 1 owner 2bbl '81 305 and it got around 18-19 MPG. Motor was gutless though.

[piecesparts]

I have a SWB that has two 16 gallon tanks. I run a 383 stroker engine with a 700 R4 tranny W/O the lockup converter. I have 3.73 gears in the rear end and with all of this, I get just over 200 Mile per tank on the truck. I do have a lower profile tire and the cruise RPMs are around 2400, due to me wanting to keep the stall converter in it's range and not overheat the tranny components..

[Skunksmash]

how many RPM's do you run with those 3:73's at about 70Mph?

[Firebirdjones]

Originally Posted by Skunksmash

how many RPM's do you run with those 3:73's at about 70Mph?

Depends on your tire height. With a 1:1 final (no overdrive) and a 28" tire that's exactly 3,000 rpms. I generally cruise at 2800 which is 65 mph.

On a truck where you can easily fit a 30" tire or more, it makes the 3.73's very street friendly.

[foamypirate]

My TBI 305/700R4 gets about 12.6mpg around town, and about 18mpg on the highway. It's waaaay undergeared though, 3.08s out back with the 700R4 just kill this motor unless I'm doing 80+mph. In which case, aerodynamics kill any chance of good gas mileage. I really want to swap in 3.73s, I could probably get up to about 15mpg around town and 19mpg highway, by my educated guesstimates.