Gas Milage
 

HEY GUYS NICE BOARD JUST A FEW ?S ON GAS MILAGE
I HAVE A 95 WITH A 350 IT GETS 16MILES PRE GALLON OK I DON'T THINK THAT IS BAD..

MY FATHER INLAW HAS A 85Silverado WITH A 305 RUNS GREAT HAS ABOUT 90.000 ON THE CLOCK BUT DOAEN'T USE OIL STILL STRONG BUT SUCKS THE GAS DOWN BAD ,HE HAS NEW PLUGS
CAP ROTOR ,,,NOT SURE ABOUT THE WIRES BUT HE GETS ABOUT 8/9 MILES IS THIS NORMAL FOR THIS YEAR TRUCK???
MAN IT IS A VERY NICE CLEAN TRUCK WOULD LOVE TO BUY IT SOME DAY I KNOW IT WILL NEED A REBUILD BY THEN
ANY INPUT ON THE MILAGE WOULD BE A GREAT HELP.
THANKS ..
SORRY NOTICED I HAD CAPS ON...:bowtie:

The 82 I had with a 305 was getting me about 15 MPG, I think 8/9 miles a gallon is not very good for a tuned up 305.

What kind of gears are in back, lower gears (higher numerically) would give you lower MPG but I don't think it would drop it THAT low.

Sounds like the carb may be hosed and in need of a rebuild...or new one altogether.

-Jeff

hey bb73 the rear is stock I know that dose not help much..
I'm may sound stupid here as far as the carb I belive it has a tbi..
dose that sound right...

if its all original then its carbed and has a Q-jet. they didn't start putting tbi in untill 87. has someone swaped it to an 87 and up motor with tbi?

Hey DLE, and welcome.

No, 85 305's had a Q-jet carb. And I agree with Jeff, 8-9 mpg sucks. I also agree it sounds like the carb may need some attention.

BTW, TBI didn't come on trucks until 87.

:confused:
HMMMM thanks for the help I thought it was a 85 ok if someone did a swap or say it is an 87 with the tbi /what can he look for to help out the milage i do know it has the tbi but I may be wrong on the year.
thanks again

DAVID

I get 16-18 in the city with a 305/700R4 tranny with 3.08 gearts. 17-19 on the highway. I would definately start looking into the problem.

I get 4 mpg!! whooo hooo... time to start looking for a good working Q-jet with some slight modifcations. Still need some gears and a small stall convertor. 2.73 gear and 32s right now.

MPG = 11 - 14

Stock 350 w/ granny 4 speed.

i get 8-9 mpg with mine:(

i need a new carb too

11 city 14 hwy 3.42 28" tires 78 350 148K all stock

screw the carb, put the gears in first, and you may not even need the converter.

HEY THANKS FOR THE HELP I STILL DON'T KNOW WHERE TO TELL
HIM TO CHECK NEXT..
NEW
PLUGS
CAP
ROTOR
RUNS GREAT STILL SEEMS TO HAVE PLENTY OF POWER
MAYBE A NEW SET OF PLUG WIRES..???I DUNNO
THANKS AGAIN



HAPPY NEW YEAR

Changed the Air filter lately !!!!

I get horrible gas mileage too, but that might be the hole in the tank too...hehe But I know shes running rich....I was putting on the plates my eyes watered right up and stung and i checked the plugs and they're wet....so I think I'm in the same boat with the carb rebuild. I was thinking about going with a Road demon jr...i don't think i'd need more then 600cfm for a stock 305? and edelbrock sells a adapter to but a squarebore onto a spreadbore...any thoughts?

my 77 silverado with 4.10's and a 400sb I manage to get 15mpg with it on the highway

Check for a collapsed cat. They can sure kill gas milage. What kinda oil is he using? Check the fuel lines for leaks at the pump and the tank switcher. Holes in tanks is a common problem too.

THANKS great tips never thought of that..yeah the darn cat
you could be on to something there.
as far as leaks it is garage kept and he would notice that.
as far as oil i will ask him...
:flag:

I don't drive vehicles with carburetors anymore.....I prefer injection pumps! :)

Diesel, man! It's the only way to go. I get 18.5 mpg average in a 3/4 ton truck w/4.10 gears! :D I actually broke 19.5 mpg a couple of weeks ago. Hadn't done that for a while. I used to get a consistent 20 mpg or better when I had 3.42 gears, and before I "tweaked" the motor a bit.

Don't forget when talking about fuel mileage, that rear end gear ratio, transmission type, and tire size are just as important as any other factor. A truck with 2.73 gears, an overdrive tranny, and large tires will usually get twice the mileage as another truck with a three-speed, 3.73/4.10 gears, and small tires, even if both trucks have the same exact engine.