Is decent gas mileage possible with this combo?

[FoFittyFoSS]

I'm daily driving my 86 C10 truck and it's killing me at the gas pump. I have been shopping for 4 banger trucks on Craigslist that will save me money commuting but won't do what I need as far as hauling loads and towing my boat and trailers. If I can get this thing from 10mpg up to 15 or better I can keep driving it. The truck is a short bed
2WD model that is lowered 2.5"/4". The motor is a rebuilt .0030" over 350 , with fresh heads, all new internals, small Lunati cam(part#60101/grind#VDSC-256) with 213/219 duration and .454/.468 lift. Otherwise the motor is stock. It has a Quadrojet of unknown origin that runs great but is not the factory carb. Distibutor is a stock HEI. 700r4 transmission with stock converter and 2.73 rear gear. I do not yet have anything locking the torque converter. What can I do to optimize fuel mileage with this combo? What could I expect to see with some changes? I don't mind spending money for some real improvements but don't want to spend a bunch for a 1 or 2 mpg improvement.
Any thoughts? Thanks, Scott.

[Bamfster]

I say a camshaft swap to something in the 190 to 210 range @ .050, multi port efi and control your right foot.

[FoFittyFoSS]

I say a camshaft swap to something in the 190 to 210 range @ .050, multi port efi and control your right foot.

I thought that was a pretty mild cam but you might be right. I would like to improve and keep the carb for now. I am not opposed to EFI down the road but right now this is what is getting me back and forth to work. A cam swap can be done in a day so that is probably in my future. Any idea of a cam that would perform better than stock and still get the mileage of the factory cam? Thanks.

[Bamfster]

I like anything that is a copy of Edelbrock's performer cam ....

http://www.summitracing.com/parts/SUM-1101/

http://www.summitracing.com/parts/SUM-1102/

And I've used both of these with good success in mild street engines.

[squirrel]

that rearend would be nice with a 3 spd auto trans, or go up to a 3.07 or 3.40 with a 700.

The cam is too big to run efficiently at 1500 rpm.

And you probably ought to run lockup, it's not difficult

[FoFittyFoSS]

I like anything that is a copy of Edelbrock's performer cam ....

http://www.summitracing.com/parts/SUM-1101/

http://www.summitracing.com/parts/SUM-1102/

And I've used both of these with good success in mild street engines.

The first cam is a big change from what I have now. The second is a little too close to justify the change. Good price on the cam. I should be able to keep the springs I have now. And I do plan on running lockup soon. When I got this truck it had no motor in it so I have no baseline to compare when it was factory. I know it is a bit of a dog now. The rest of the combo is not ideal for the cam that it has. Anyone have real world experience with these old Chevy trucks and what kind of mileage I can expect to see?

[Beagle]

that rearend would be nice with a 3 spd auto trans, or go up to a 3.07 or 3.40 with a 700.

The cam is too big to run efficiently at 1500 rpm.

And you probably ought to run lockup, it's not difficult

Agreed but I think he's stuck on the carrier? My 86 had a TH350c, 305 4bbl, pretty sure it had 3.08's ... you should see at or over 14-15 avg with 50/50 city/hwy and with less intake duration (a lot, echo echo echo) and it should feel stronger.

[squirrel]

15 or better should be possible if everything is working right together.

wife's 99 with the 325 ci "late model" engine gets 19-20, with 3.73 gears and kind of tall tires. I've got 15 city/20 highway with overdrive gearing with a very mild 350 in an old street rod, with overdrive and 3.23 gears

I get 11 in my 57 one ton with a big block and granny 4 speed and 3.73 gears....city and highway is the same.

[FoFittyFoSS]

http://www.fueleconomy.gov/feg/bymake/Chevrolet1986.shtml

Funny how a couple models from 1986 are as good as todays hybrids. My truck came with a 305 from the factory so I can't find anything here to compare it to directly but it looks like 15mpg is what I should expect.

[Beagle]

They put a 350 TBI EFI in 87, you had to go over 1/2 ton for a 350 in 86.

[kyhunter89]

run a toggle for the lockup, and lower rear gears will help. You have overdrive, use it to your advantage. Where do you drive mostly?

I run back country roads and going from 3.42s to 3.73s gave me 2mpg.

[Bamfster]

I had an '80 shortbed 4x4, 350, 4 spd, 4.10 gears w/ 33s. I set that up w/cam #2 that I listed, performer intake and 600 V/S carb, it was nothing more than a stock rebuild engine.

City it got 14/15 and highway was 19/20 .... ish. The funny thing was, without the tonneau cover, highway was the same as city.

There is a ton to be had w/ carb and ignition tuning for good economy. And like Jim said, everything needs to work together.

[yellomalibu]

In my 82 C10 Blazer with 3.08 (ish) gears, 700R4, 350 - I get about 15 on the highway.
The 350 was a 92 TBI engine. I have a Holley 600 vac sec with a cross wind intake ( air gap knock-off by PP), small diameter headers, and an Elgin E-923-P cam.
Cam specs:
420/443 lift
270/280 advertised duration
204/214 @ .050
107/117 lobe centers

My 84 C10 with stock 305 and a manual transmission only gets 13 on the highway... That emissions crap doesn't seem to help fuel mileage.

[Scott Liggett]

Start by checking your current set up. Make sure that Q Jet isn't leaking fuel from the bowl plugs (very common). Also, check it's tune. Are the plugs reading black, or rich? Changing metering rods may pick up the mpg a bit.

I agree that 2.73's with a 700R4 and that cam don't match for best efficiency. I bet it's lugging along at barely 1300 rpm on the freeway. Try leaving it in 3rd. See if that helps mpg a bit.

These are cheap things to try before getting into the wallet for real fixes.

[FoFittyFoSS]

Start by checking your current set up. Make sure that Q Jet isn't leaking fuel from the bowl plugs (very common). Also, check it's tune. Are the plugs reading black, or rich? Changing metering rods may pick up the mpg a bit.

I agree that 2.73's with a 700R4 and that cam don't match for best efficiency. I bet it's lugging along at barely 1300 rpm on the freeway. Try leaving it in 3rd. See if that helps mpg a bit.

These are cheap things to try before getting into the wallet for real fixes.

I will try that on the way to work in the morning.