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gas hog?

guz71

1/2 ton status
Joined
Sep 17, 2006
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lubbock/houston
I daily drive my K5 and the 350 just isnt cutting it. I was planning on dropping in TBI 383 (class II) engine from jasper this summer but im kind of nervous. I know that the truck is never going to be anywhere gas friendly the but my current 10 mpg around town isnt to horrible (13ish on the highway) but Im worried that the 383 is going to suck gas down like beer? I would think it wouldnt be as bad since the motor work near as hard, but then again the motor is bigger and more agressive. That model isnt real radical, but definately a signifcant jump. Opinions? if not a lot of other goodies are going on:rolleyes:
 
I doubt the 383 mileage will be much worse, if any.

My 305 K5 got the same mileage my 350's did in town. (10-13 depending on how I was driving) My dads 454 in a 6000# truck gets 9MPG in town.

With your mods, I see no way to improve your mileage enough to worry about anyways. Only question is, however you are measuring mileage (odomoeter?) is IT accurate? Many seem to make the mistake of saying they get really good or bad mileage, but do not take into account speedometer errors. GPS will work.
 
I better running, more efficiant enging will sip less gas than a worn out inefficient engine. So if your 383 is built right, with enough compression and the right cam you should pick up some gasmileage. :)

~Brian
 
Brians89K5 said:
I better running, more efficiant enging will sip less gas than a worn out inefficient engine. So if your 383 is built right, with enough compression and the right cam you should pick up some gasmileage. :)

~Brian

If you can keep your foot out of it...:D
 
True, throttle positioning is where its at in terms of gas mileage. My dad and I bought exact same S10 pick up trucks. Both had the 5 speed and extended cab. Mine had the V6 in it and his had the 4. Even though I had double the displacement I made 4 to 5 mpg better than he did consistantly. UNLESS, I was on the throttle, then that 6 would drink a little harder. I think I only got worse gasmileage than him once in the year we owned our trucks. I had more fun driving my truck to as he would always be trying to catch up. :D

~Brian
 
yeah the speedo/odo is pretty darn close. The 350 is a crate and only has 30K on it but I dont think its running all that great.
 
have you checked the basics like timing and ignition system? plug condition? fuel mixtures? 30k is pretty low homers.
 
I think its fine actually, I drove a tahoe with 4.56's and had some mods on the motor before the blazer so it was like a bat out of hell 0-60, so im just being a little power hungry
 
need to find that guy on here who claims he's getting 25mpg on the highway with his gasser 350TBI/700r4 suburban with 3" lift and 35" tires,,,,

see what exactly what HE did to get that kind of mileage:haha:
 
4xcrazy said:
need to find that guy on here who claims he's getting 25mpg on the highway with his gasser 350TBI/700r4 suburban with 3" lift and 35" tires,,,,

see what exactly what HE did to get that kind of mileage:haha:
lol must have bought a flux capacitor and added a NOS sticker....
 
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