bad mileage???

[85mudblazin]

I have this 350 and my problem is that I only get about 7MPG per gallon, I have the stock carb and intake, with headers, does anyone know why I get such bad mileage?? This is the 350 that I have

 

[4xcrazy]

I get 10 in my Burb around town, but mine is also fuel injected.

oh, the other thing,,,5000+ pound vehicle your tryin to move there.

 

[85mudblazin]

yeah that is tru but I thought I would get a little better than 7MPG /forums/images/graemlins/doah.gif
Also I have 35" tires and I was wondering if changing out my gears would help my MPG any? I am think about getting 4.56 gears.

 

[mtnman210]

I'm running a gm crate 350 with a holley 600mcf card. I've got a 6in lift with 35 bfg mud/t and 4.56 gears i very between 7-9 mpg. so really you're right about where you mileage will sit. maybe changing gears might help a little but not much.

 

[87BrnRsd]

4.56's and 35's will suck gas around town and on the highway unless you have od. I am running 37' mt/r's with 4.56 gears and a 700r4 od tranny, plus I have tbi fuel injection, and I still average about 8 mpg around town. Highway is a little higher, maybe 11-12? As stated above, your trying to move a 5000lb+ truck, that is about in the shape of a box. Not very aerodynamic, and 350's in our blazers arent the most efficient engines on the market...
BTW what gears are you running now?
-Harrison

 

[scoutillac]

I am barely getting 10 in the city with a fresh rebuild. I do have a bigger cam, K&N, TB spacer, and Jet chip. I am hoping to get a mile or two more when the engine gets broken in. I also have 35's and 4.56's 350 tbi 700R4 np208 blah blah blah

 

[ratzila]

I have a 454 with bigger cam,800 cfm quadrajet, headers,th400, 5.13 gears & 44" boggers and it gets 8 mpg on the interstate /forums/images/graemlins/woot.gif

 

[85mudblazin]

I have the stock 10 bolts front and rear but I dont know what gears they have in them, what ever is stock is in there. /forums/images/graemlins/thumb.gif

 

[Bhintz]

if you want new gears I would just upgrade the axles to 10/14 or 44/14 b/c its about a grand cheaper and you get the gears you want and more strength and if your running a 350 or 400 trans Id go with 4.10s and not 4.56s

 

[darkshadow]

[ QUOTE ]
I have a 454 with bigger cam,800 cfm quadrajet, headers,th400, 5.13 gears & 44" boggers and it gets 8 mpg on the interstate /forums/images/graemlins/woot.gif

[/ QUOTE ]
Ratzlia i love you truck all the more /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif

Thats impressive for your beast

 

[gravdigr]

[ QUOTE ]
and 350's in our blazers arent the most efficient engines on the market...

[/ QUOTE ]

The 305 is even worse. I might pull 10mpg with my 86 carbd 305 but with the mountains here it's usually closer to 7-8. I'm installing a 350 in hopes of getting better mileage.

 

[ratzila]

When I had the 39.5 tsl & sm465 it would only get 6 mpg.
Switching to the t400 & 44's lowered the rpm's and raised the mpg's. /forums/images/graemlins/thumb.gif