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Thread: V8 Mpg

  1. #1
    BlazinLow Pilot SlimGu3's Avatar
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    V8 Mpg

    I really want a to drop a small block in place of my gutless 2.8. What's this going to do for my gas milage?? I have gotten it up to 16mpg, is that going to go to hell?
    I like my trucks like I like my women; WHITE & SHAVED!

  2. #2
    Creative Genius
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    I don't know for sure, but it would seem to me that gas mileage wouldn't be any different. I mean, if you think about it, when you drive your 2.8, you pretty much have to floor it to do highway speed, now that uses pretty much the exact same amount of gas as a 350 half way to the floor. The 350 has to do less work, and in turn, should not use that much gas... maybe I'm wrong, but to me, it stands to reason.

  3. #3
    Moderator 8mpg's Avatar
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    My name says it all.

    Well, I assumed you would have gotten the idea of my name.
    I get around 8mpg, thats not just stepping on it, nor staying in two barrels.
    I did not set up my blazer to get good gas mileage. I have a Edelbrock 750 and all new HI-PO fuel pump, lines, filters. You could go with a smaller carb for a 350. Like Blazin low. He has a MUCH nicer carb than I do. Probably gets better performance with less fuel.

    Then again, you could go with a holly projection fuel injected manifold. Usually with fuel injection you get better gas mileage. My doctor has a 383 with a holly projection system on it, It has more horse power than mine does, and it gets 18 miles to the gallon he says. So basicly It really all depends.

    And you are right to some degree. But, a 2.8 vs a 5.7 thats double the displacement. Two more cylinders, all all of them are much larger. Say you have a 2.8 carburated, and a ,5.7 carburated. If you took the mass of the cylinders that suck the air and gas. Technicly its going to be doubled due to the size of the displacement. I am sure you will get more power, but thats just because of the larger pistons, and the added number of them. It still takes that much gas to push them up and down.

    My logical two cents.
    Hold my hammer while I nail your girlfriend

  4. #4
    BlazinLow Pilot SlimGu3's Avatar
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    If I knew I could get 18mpg I would do it ASAP. I'd love to be able to rip shit up at the street races, but not for 8mpg. What do you think about just a simple 2.8-4.3 conversion? Can I get some horses out of a 4.3?
    I like my trucks like I like my women; WHITE & SHAVED!

  5. #5
    Moonwalkin' Moderator Nitro18's Avatar
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    yes

    CPI r0x
    '92 S-10
    Vortec 4.3L CPI engine
    MSD ignition control unit
    ACCEL wires & components
    BLAZIN it down the streets of Bellmore

    MTX/Rockford Fosgate system
    280 watts of sub-pumpin power
    400 watts rippin those highs and mids
    all faced by a Pineer DEHP4100

  6. #6
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    better

    Some good news some bad.
    I have a 350 out of a 76 van. With a 4bbl. But I used the 700R4 Trans.
    The old motor (if you can call it that) was a 2.8 with over 100,000 on it. I get 21 hwy, and 12 city. (but it all depends how you drive it)

  7. #7
    Moderator 8mpg's Avatar
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    Yeah, if you get the 700, it has an overdrive so you can get better gas mileage. Also if you can afford a holly projection fuel injection kit like i said, you can get really good gas mileage with even better performance.
    I dont get good gas mileage, and personally I do not care. I figure if your worried about gas mileage you shouldn't have a v8 anyway. Just the sound of the blub blub blub. Thats worth all the gas in the world in my eyes.
    Talk to nitro18 about the 4.3's he seems to know what hes talking about on those.
    Hold my hammer while I nail your girlfriend

  8. #8
    Registered User Rcv's Avatar
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    I use a Holley 3310-2 on my 350 which is either a 750 or 780 cfm vacuum secondaries. With 3.73s, 700R4, 275/60R15 Radial T/A 28 inches tall, and a weight of 3660 lbs I get 15/18 driving like a normal person.

  9. #9
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    i only get like 5-8 mpg and i have 3.73 with 700r4 but i guess its cause i drive it the way you are supposed to drive a v8 s10 Drive it like you stole it! you cant resist with 400 hp! :)

  10. #10
    Slow Ride
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    I must be special

    I have a 10:1 - .040 over 350 with Dart heads a fairly big cam and headers. I also run a 750 cfm Edlebrock carb.

    I have a 700R4 and 4.10 gears.

    I get on the highway about 26mpg and about 6 mpg in the city but I have a heavy foot.

    I must be special or something to be getting this kind of milage.

  11. #11
    Registered User Rcv's Avatar
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    Driving like a maniac slamming it no matter what I still get 10-12 mpg. That's with Vortec heads, Edelbrock Performer Intake, and a CompCam XE268H.

    I don't know about 26 mpg on the highway. That's what my moms 99 Lumina gets and it's more aerodynamic, has a smaller 3.1L engine, fuel injection, 3.33 gears and .71 OD.
    Last edited by Rcv; 10-24-2001 at 02:41 PM.

  12. #12
    Moderator 8mpg's Avatar
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    Yeah speaking of driving mine like it should be driven. Because of that damn thing I just lost my license for a year.
    God damn.

    Neglegent driving.

    Thats my fifth ticket in two years.

    I am 17, and in washington state they have a law that says if you have 6 points on you license in two years you loose it for a year.

    So it is parked now.

    I guess the money I save from gas and insurance I can just put even more money into my motor. And some really fat tires and posi, cause thats how i go into this mess. Damn those tires. They just beg to spin.

    oh well
    Hold my hammer while I nail your girlfriend

  13. #13
    BlazinLow Pilot SlimGu3's Avatar
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    Well I really want to drop a 350 in place of that damn 2.8. Everyone has done this! All you guys act like a V8 here, a new trany here, and some 3.10 gears there, are like a piece of cake to get. Am I missing something? The only reason everything on my blazer is shaved and it's bagged, is because I know how to do that stuff, so it's cheep. But how does everybody throw in 350's like it's changing the oil? Do you find 'em at a bone yard?
    Oh yeah, has anyone bored over a 4.3? What's that like?
    I like my trucks like I like my women; WHITE & SHAVED!

  14. #14
    Registered User Rcv's Avatar
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    My uncle got a 95 4.3L out of a 4 door Blazer and put it in his 89 S10. It's bored over .03 has a cam, headers, ported heads, chip, single 2 1/2 exhaust and runs 15.2s @ 90 mph at the track. Only problem is CMFI is shit that's why all that work and it's still a turd. Gets 25 mpg though.

  15. #15
    Slow Ride
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    4.3 engine work

    A 4.3 is a 350 with 2 cylinders cut off, because of this they are relatively cheap to build up. I have one bored .060 over with domed pistons and aluminum heads. It made over 400hp but was a little low on torque (cube and stroke make torque). If you really want to get crazy put in some dished pistons and bolt on a 6-71 Blower with either injection or carbs. There is nothing more beautiful that a gleaming blower sticking out of the hood.

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