How can i improve a lil bit on gas mileage
 

I have a 383 stroker with dart heads single plain intake and a 600cfm holley 3.23 gears highway stuff, i get up go to the gas station get $10 worth wich is about 2.5 gallons of gas, go to school wich is barely 8 miles away come home dont go anywhere get up the next morning all my gas is gone whats the deal here? i have a locking cap so noones siphoning my gas idk what more to do specially with gas prices the way they are.

Re: How can i improve a lil bit on gas mileage
 

It's because you have "a 383 stroker with dart heads single plain intake". That single plane and those Dart heads are designed to flow fuel, not sip it. Great for grins, but not so much for MPG.

Best solution is to park it and buy a cheap small car or truck.

Re: How can i improve a lil bit on gas mileage
 

Ditto !

Or maybe slide a block of wood under the gas pedal ? ;)

Re: How can i improve a lil bit on gas mileage
 

I drive the speed limit even under to save gas lol and i thought about parking it but i like it but theres gotta be a way to get better we built a 388ci in a corvette and it got 16-17 mpg with aluminum heads

Re: How can i improve a lil bit on gas mileage
 

Have you checked for any fuel leaks, Like the tank sending unit hoses ?

What tranny you run'n ?

BTW, I'm hotter in Fl too.... :lol:

Re: How can i improve a lil bit on gas mileage
 

Havent checked for leaks but ive been wanting too just havent got the chance also running a th-350

Re: How can i improve a lil bit on gas mileage
 

:haha:

Re: How can i improve a lil bit on gas mileage
 

Whats so funny? i didnt ask for any smartass remarks thanks though :chevy:

Re: How can i improve a lil bit on gas mileage
 

take a golf ball and throw it. then take a brick and throw it. witch one goes farther

golf ball made to cut through the air like a corvette
brick dosnt cut through the air like a SQUARE BODY truck

just saying your comparing apples to fire wood

horsepower and gas milage together is an oxymoron

Re: How can i improve a lil bit on gas mileage
 

So im an oxymoron? figured id post here so i wouldnt get bashed but its starting to look like it thanks for the help NOT i guess i wont post here anymore

Re: How can i improve a lil bit on gas mileage
 

I'd pull a couple spark plugs and see if their black from running too rich, If their not black start hunting for leaks. I just can't fathom that SB drinkin gas like that, My 502 LUVS it but still gets 13 mpg....

Re: How can i improve a lil bit on gas mileage
 

I will check that tomorrow im in the mixed of getting a GOOD air cleaner too, thanks you seem to be the only one helping ;)

Re: How can i improve a lil bit on gas mileage
 

383, chill.

Your setup is not going to pull the best MPGs, these heavy trucks arent exactly aerodynamic either. Id triple check timing, maybe set carb. with vac guage and go easy on the pedel. Maybe think about OD trans in the future?

Re: How can i improve a lil bit on gas mileage
 

I am chill but laughing at something thats not a laughing matter is stupid, im pretty easy on the pedal i dont speed or lead foot i dont have the money for that does the 700r4 only had OD or does the th-400 have it?

Re: How can i improve a lil bit on gas mileage
 

no one means to be mean its just there's not much hope for our trucks with horse power like a 383 puts out. change the intake put on a quadrapuke on top of it if you dont have to demanding heads and cam, change out the gears in the rear end, but even then maby a maximum of 15 mpg

Re: How can i improve a lil bit on gas mileage
 

So, 16 miles divided by 2.5 gallons = 6.4 mpg - correct? The most accurate way to check fuel mileage is to fill up the tank, drive it a few days, fill up the tank (same pump, same level) and divide gallons used by miles driven. In my experience, a stock V8 pickup is good for 10 mpg city at best - less in winter with 10% alcohol in the gas. I lose about 1.5 mpg in the winter with my 454 C20. Check your fuel inlet nut at the carburetor- if gas leaks there it evaporates on the intake manifold so you never see it leak - might smell it though. I would not expect more than 8 mpg with your setup, unless you are on the highway with that 3:23 rear.

Re: How can i improve a lil bit on gas mileage
 

I still think i have a good leak i was getting 14 with 4.11 gears a couple months ago its even cut to 2barrels instead of 4 its the damndest thing i cant figure this truck out i was getting almost 16mpg with 4.11s and 315 drag radials i put 33" a/t's and i went down to 14 then down to 10 then back up and back down switching back and forth from 2brl to 4brl, i know the filler hose has a small crack at the end so i spill a lil bit of gas out while pumping but its got to be evaporating or something from somewhere i already had a fuel inlet nut leak and i took care of that

Re: How can i improve a lil bit on gas mileage
 

Just a side note; I drove my 74 as a DD for 8 yrs, Stock 350 2bbl turbo 350 and the BEST it would do is 10.5 mpg even after a carb rebuild and EVERYTHING in the ignition system new and fine tuned....

Re: How can i improve a lil bit on gas mileage
 

Wouldnt a manual 4 speed help with mpg? we just had a 85 suburban 3/4ton 350 with the 4 speed got close to 17 mpg's

Re: How can i improve a lil bit on gas mileage
 

get a vaccum gauge and learn to keep it all the way to the right.. ='s best mileage for what you got...

you still running the 33's? i'd put the 4.1's back in... especially if you're not doing and highway.. ie cruising at 50 or w/e should make the engine run a lot easier.. thus use less fuel even though you may turn a couple hundred more rpm.

Re: How can i improve a lil bit on gas mileage
 

4.11's got stripped out so 3.23's were all i got but with the 4's it screamed like 2400 ish rpm im at 1600 rpms at 55

Re: How can i improve a lil bit on gas mileage
 

What about trying a lower rear end gear, like 3.73. You said you were running 33 inch tires, with a 3.23 rear end. That would be similar to a stock tire turning a set of 2.73's. No matter how powerful an engine is, it will always take a little more effort to turn a taller set of gears.

The chart in this link may be able to better get my point across.
http://www.4lo.com/calc/geartable.htm
Yellow = better economy
Green = everday driving
Red = more power

Re: How can i improve a lil bit on gas mileage
 

Mongoose beat me to the punch, 1600 RPM is lugging the motor.

Re: How can i improve a lil bit on gas mileage
 

I may look for some 3.73's initially i thought they were 73's till igot them and counted and it came out 23's ill see if i can find them though thatd prolly help out a bit

Re: How can i improve a lil bit on gas mileage
 

You killed your mileage in the process of trying to find more. Switching to a 2bbl will almost always hurt gas mileage. Going to taller tires with a higher gear has you somewhere around the equivelant of a 2.73 gear. Your lugging your engine by having the rpms so low during cruise. Go back to the 4bbl and put some more gear in it. MId 2k rpms is where a small block likes to be. Lower rpms is not always better. If you were getting 14mpg with a 383 in a heavy truck you should have left it exactly how it was because that it real good mileage for one of these old pigs with the aerodynamics of a brick.

Re: How can i improve a lil bit on gas mileage
 

Is your truck 2 or 4 wheel drive? My 383 has been getting 10-12 mpg, depending on how it's driven.

Re: How can i improve a lil bit on gas mileage
 

Prolly gonna hook the 4 back up tomorrow and find me some 3.73's

Re: How can i improve a lil bit on gas mileage
 

2 wheel

Re: How can i improve a lil bit on gas mileage
 

'screaming' or not... fuel efficiency is about volumetric efficiency.. where your rpm's land is where they land 'screaming' is usually better than lugging around...

Re: How can i improve a lil bit on gas mileage
 

i had a 83 swb with a hot sb 400 most the parst came out of my dads super street race car it had a high gear and 700r4 with a 4bbl holly 600+- and was able to get 15 must have just been that right combo of course when i got into it it would kill a tank in a hurry

Re: How can i improve a lil bit on gas mileage
 

Well imma just hook the 4brl up gets 3.73's gears and still check for leaks just incase i appreciate it guys

Re: How can i improve a lil bit on gas mileage
 

so you have a 2bbl 383, with a th350, 2wd with 33" tires and 3:23 rear gears? first put the 4bbl back on and give it a tune up, plugs, wires k&n filter, timing set prop. then change the tires to something normal say around 28". even 31's would be better than the 33"s. that should help some, then look for a 700r4.

Re: How can i improve a lil bit on gas mileage
 

no your statement was an oxymoron after reading all the post AFTER my post you give possible reasons why your truck is getting bad gas milage but prier to my statement all you said is you have a built motor and you dont understand why its not getting the same milage as a car that 2/3 the weight and one of the most aerodynamic vehicles gm ever built

and now with that said you pointed out one thing that needs to be fixed first. you said the filler tube hose has a crack in it
your sucking air in to the tank and you have an open system that works best closed with negetive pressure. its just like leaving the gas cap off
whats happening is your pump can suck MORE FUEL easier because it dosnt have the back pressure and by not having the back pressure it also creates a syphon

Re: How can i improve a lil bit on gas mileage
 

Just so you know...An oxymoron is a figure of speech that combines contradictory terms. Oxymorons appear in a variety of contexts, including inadvertent errors such as extremely average :lol:

Re: How can i improve a lil bit on gas mileage
 

Right that will be fixed soon i dont have the money at the moment like i said i got it all figured out now because you guys helped thanks :metal:

Re: How can i improve a lil bit on gas mileage
 

all you guys with 383's+ are making me feel bad about my 305 with a mild cam getting 9mpg :(