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09-15-2008, 04:55 PM | #1 |
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350 /454 mpg differences
In 2 trucks exactly the same except one having a 350 and the other a 454 , how much of a difference would there probably be on mpg for the added cubes ?
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09-15-2008, 04:59 PM | #2 |
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Re: 350 /454 mpg differences
350 = 15 cty/19hwy
454 = 9cty/12hwy
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Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com |
09-15-2008, 05:05 PM | #3 |
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Re: 350 /454 mpg differences
Depends what components are in each motor. If your 350 is built with huge heads/cam/intake and the 454 is a low compression stump puller, the bbc may get better mileage. Captkaos is probably pretty close if both are stockish low compression builds.
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'85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD |
09-15-2008, 05:20 PM | #4 |
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Re: 350 /454 mpg differences
agreed
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75 GMC C-15 short/step factory 454, lowered |
09-15-2008, 07:29 PM | #5 |
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Re: 350 /454 mpg differences
are those numbers based on late model type motors with EFI? Art
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Art 1975 c-10 stepper 1978 single cab dually 1987 crewcab dually 1986 crewcab single wheel 1948 anglia- (the dixie twister super gas) |
09-15-2008, 11:44 PM | #6 |
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Re: 350 /454 mpg differences
No, you can expect about 2-3mpg gain on a TBIsetup.
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Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com |
09-15-2008, 08:17 PM | #7 |
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Re: 350 /454 mpg differences
I measure my 454 by the number of gas stations I pass, typically 6
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Lil red 86 c-10 99 Sub 78 Camper Special w/ 454 |
09-15-2008, 09:34 PM | #8 |
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Re: 350 /454 mpg differences
my mild built 454 averages 11MPG, with 31" tall tires & 3.73s. best I ever recorded was 13 MPG, all hiway, no AC running around 60-65 MPH. 70-75 MPH it gets noticably worse
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75 GMC C-15 short/step factory 454, lowered |
09-15-2008, 09:38 PM | #9 |
One day...
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Re: 350 /454 mpg differences
Ah heck, in all these cool rides who cares
But the DD thats another story |
09-15-2008, 10:40 PM | #10 |
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Re: 350 /454 mpg differences
i went from a 305 to a 358 and i really notice a big difference.
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1986 chevy c10 in the "build" process as we speak 358 flat tops, vortec heads, .500 lift cam, NOS power shot plate system, yada yada yada MMA PIX http://www.clgpix.com/MMA/Fighters/F...C/CoteTony.htm MMA RECORD 24-5 |
09-15-2008, 10:25 PM | #11 |
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Re: 350 /454 mpg differences
Bowed: My cousin has a 78 Big 10 350/350 and I have a 78 Big 10 454/400. Trucks are exactly the same, except for the engines/trans. We both get about the same mileage, 10-12 mpg.
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09-15-2008, 11:37 PM | #12 |
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Re: 350 /454 mpg differences
A good or bad difference?
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09-15-2008, 11:47 PM | #13 |
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Re: 350 /454 mpg differences
x2 I've heard from a lot of different people the 305 is actually just as bad or worse at fuel consumption than a 350.
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09-15-2008, 11:59 PM | #14 | |
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Re: 350 /454 mpg differences
Quote:
My 305 in my R10 gets 17/22. My 350 in my R3500 gets 13/17. These are actual averaged numbers as I check these regularly.
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Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com |
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09-16-2008, 02:07 AM | #15 |
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Re: 350 /454 mpg differences
I think mileage has to do with how efficient a motor is running for that particular application. I think a 454 that has been worked over with raised compression, improved cylinder head flow, a larger but not overly radical cam, and a free flowing exhaust could actually get the same or better mileage than a low compression smog 350.
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09-16-2008, 09:22 AM | #16 | |
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Re: 350 /454 mpg differences
Quote:
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'85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD |
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08-05-2016, 06:56 PM | #17 | |
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Re: 350 /454 mpg differences
Quote:
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09-21-2008, 10:00 PM | #18 | |
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Re: 350 /454 mpg differences
Quote:
I was getting 6.5 mpg on my running on a miracle 350 right before it gave out
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08-24-2013, 03:47 AM | #19 |
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Re: 350 /454 mpg differences
well it being a 454 wouldnt it get worse gas mileage but tow the s**t out of a 350 since they both stock.... now if you have a stock 454 and who cares how much it costs 350, throw two carbs on it 350... well might be a different. story also how are you driving it..? now my father has a 77 single cab one ton dually with a 454 in it and accelerates as fast the truck will go without pressing on the gas(he had a 55 hard top with an ls 454 in the 70's built at baxters in delta in park portland, oregon, he had his fill of speed) and still complains about gas mileage. but on a side note, i asked if they would lump port a 292 head and they said no, its to risky, come on now. but anyways. it just depends.
but personally engines are built for what they're charging for gas at the time....
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79' c20 std cab 292 3speed granny - daily driver. 77' c30 std cab 454 th400 4.10 - fathers truck then mine. 95' ford bronco 302 4speed overdrive. 2002 mustang auto v6 - girlfriends daily driver. Debt just means that you had more fun than you're suppose to have |
09-16-2008, 09:28 PM | #20 |
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Re: 350 /454 mpg differences
well its hard to compare the 305 was a stock 86 with a edlebrock 600 and the 358 is a 10 to 1 compression with a holley 750. but the 305 was around 16-17ish on average the 358 was really ****ty on my last trip on the highway trying to keep it at 80mph with a th350 tranny was probably the problem got 11-12
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1986 chevy c10 in the "build" process as we speak 358 flat tops, vortec heads, .500 lift cam, NOS power shot plate system, yada yada yada MMA PIX http://www.clgpix.com/MMA/Fighters/F...C/CoteTony.htm MMA RECORD 24-5 |
09-16-2008, 12:03 PM | #21 |
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Re: 350 /454 mpg differences
I'm getting 14MPG out of the 350 I swapped in place of the 305. Used the same TBI. Haven't really done any fine tuning yet, will probably do better.
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09-16-2008, 12:45 PM | #22 |
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Re: 350 /454 mpg differences
I get about 11 on the highway in my 454 powered '77 dually. That's running around 65 mph. The faster I go, the faster my tanks empty.
I get around the same in my '88 K20 'Burb with the 350 on 33's. My theory is that little 350 is working a lot harder than the 454-hence the mileage discrepancy. |
09-16-2008, 03:31 PM | #23 |
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Re: 350 /454 mpg differences
My 1980 step with 454 is pretty hard on gas - at the most 12mpg - if I beat on it, I can almost see the gauge go down.
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09-21-2008, 09:55 PM | #24 |
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Re: 350 /454 mpg differences
Sorry for the hijack but, what octane are you guys running on with your higher compression motors?
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09-22-2008, 09:40 AM | #25 | |
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Re: 350 /454 mpg differences
Quote:
8.3:1 dynamic .039" quench pad 34* timing runs on 91 octane all day long
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'85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD |
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