Gunny Highway

iTrader: (1)

Just wondering what other 350 guys are getting for gas milage. I'm getting around 200 miles to the tank with 3.23 gears and an auto and only 1 chip burn. Mods are in the sig.

I'm just trying to figure where I stand.

GTAfanatic

iTrader: (3)

I get 10.98 miles per gal around 170miles/per tank full (15.5gal) with a 355 with 373 gears it kinda sux fill up cost like $32 or so and it dosn't even last me a week

ShiftyCapone

iTrader: (7)

With the right tune there is no reason to see anything less than mid to low 20's on the highway.

Gunny Highway

iTrader: (1)

According to my calculations, I'm getting about 13.6 in the city with what some might call "spirited driving." That's not too bad I guess, considering more power generally equals less milage.

JPrevost

I can't muster better than 14 city, usually 12 under normal driving. I was able to squeeeeeze the 14 when I was trying hard, haven't tried since.
Highway is in the 23-24 range right now with highway mode set relatively low, it's commanding a 15.5 AFR now, noticed no difference in milage between this and 16.5 AFR. Tried running no highway mode and milage dropped to 20.
My setup, 350, cam that has too much overlap and not enough lift, 3.73 posi and a 2800 stall converter. I bet I could get over 28 highway with 3.08's out back or a T56. The high stall TC doesn't help either. It's actually done NOTHING for me in the 1/4 mile. I'm thinking about going back to the 5000 mile stock replacement one I have sitting here. Really though, it's a 12" slop bucket. I'm too embarrassed to even tell you how much it slips even ABOVE it's rated stall speed. Let's just say that I shouldn't need to shift into 4th gear but the valves are floating in 3rd at 5300rpm .

vic_V8

i can get 16 in my Truck. Its a 350 TBI, and out weighs us by about 2,000 lbs, it has 3.73 with (31" tires, about the same as having 3.08-3.23 in the camaro)

BMmonteSS

I can get 13-14 around town, and I average 21 most of the time with about 200 miles on the highway and 60 around town. I've gotten a best of 23 on the high way, but that wasn't even at the speed limit, I probably averaged 75 mph on that trip. I'm also running 3.23 with a 700-r4, but in a heavier less aerodynamic brick. I'm also not running high way mode either.

kamaroirock

its says on the inspection dyno that my 350 tbi is sopposed to get 16.5 mpg with 3.42's

JPrevost

How in the world are they coming to that conclusion with it on a dyno? How can they detect how much AE is being used, highway, city, how much deceleration you use, etc. I say they're blowing smoke up your tailpipe to say you SHOULD get 16.5 mpg. Drive the car and do your own milage calculations that dipict your ACTUAL milage.

adambros

iTrader: (2)

sounds about right. . .
Im getting 20-22 miles per gallon on the freeway and roughly 15 driving around town.

GOY

HOLY CRAP! My lo5 tuck gets about 10 MPG and I'm running 285/75's ! Then again, my lo3 'Maro gets about 14-15 city, so guess which one I drive more?

What have you done to your truck to get that mileage?

V8Astro Captain

iTrader: (1)

I had an L05 (converted to roller cam using the Ram Jet roller cam, Edelbrock 2101 intake, 3.42 gears) in my '92 Astro that got an average 21.5 mpg.

This was after alot of PROM tuning.

Keith5

I have a 350TBI truck aswell. I get 16.5 mpg highway. The truck has 200K on it, and it is the orignal engine, never been touched except for the water pump and tune up items.

The truck has 2.73's, and it is 2 wheel drive long bed.

My Firebird(305 TBI) is getting 22 and 23 mpg now.

Cadillac

FWIW, my stock 305 gets pretty crappy mileage around town... no more than 12-14 MPG. On the road however it is a different story. Maintaining the speed limit (or a little higher) I've been as high as 26 MPG even driving up the Santa Cruz mountains!

vic_V8

sorry, been on break

truck mods: 180 stat, Electric Fan, Open Element, TBI spacer, no cat, full synthetic oil, new radiatior, full tune up, 2 inches of sus. lift, sittin on 15 x 10s.

Last summer I was getting 20.5 with the AC on, not really sure what happened.

SB406

My best was 20.9 MPG with my 406 in a chevy van running on 350 TBI with no tuning and 3.41's. The setup is in a lighter vehicle now and I'm gonna tune so it should get better. As of right now, it's getting 15.5 MPG in my shortbox chevy pickup with 3.08's (same tire size) I realized the problem today though....When I transplanted the wiring, I left out the 2 extra wires going to the brake switch! The TCC won't lock up! After fixing that and tuning in the spring, I'll let you know. Should be much better.

SchwarzCamaroRS

i dunno how, 350TBI/700R4/2.73 rear i got 330 miles on 13 gallons... thats right about 30 mpg... but it was 100% freeway, nonstop 4 hours of driving.. AZ to CA... i was going 95-100mph the whole time and drafting whatever cars i could... normally i get at least 25mpg on the freeway... all city, i usually get 210miles on the tank... but i drive, i dont cruise... bruce might have a power possessed LO3, but ive got a mpg possessed LO5

r90camarors

My old 383 setup w/ a t-56 and 3.73's yielded 26mpg hw. After I swapped the rpm airgap on there it dropped to 24.5-25mpg hw. It made better milage at 80mph than 65mph, though a lot had to do with the powerband/tranny/rear/tire combo which put me at just over 2k rpms at 80mph IIRC. That was with holley tbi w/ 85pph injectors

walterrao

i get about 25 highway dooing 75-80 2400-2500 rpm, and around 18 around town. i have 327 gears, a vortec 355 10:1 compression lt1 cam. I've gotten 350 miles out of a tank

scubas_90rs

im getting about 28-30 on the highway and about 15 in town(but my toenails are very short on the right side). I have a 350 5speed and 3.42s origanal chip from the lo3 no tuning done to it.