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Big Block vs. Small Block

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by wayne, Jan 23, 2002.

  1. wayne

    wayne 3/4 ton status

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    I was checking into a few things for a comparison between the two and was wondering if there is really a need for a big block when your running a doubler. I guess for mud and big torque numbers a big block is the way to go but I don't see the justifacition with the cost difference. Here is what I came up with for a modified truck with a lift and gear change and I think it is close to real world figures,

    TBI Small Block
    10,000 miles a year
    13mpg
    769.2 Gallons of gas
    $961.25 a year at $1.25 per gallon

    TBI Big Block
    10,000 miles a year
    8mpg
    1250 gallons
    $1562.50 at $1.25 per gallon

    Difference of $601.25

    Also figuring the cost to build the big block will cost about a $1000 more and small block parts are everywhere so is a big block really worth the cost.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  2. speed_deed

    speed_deed 1/2 ton status

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    I would go smallblock just for the price!

    '85 k-5 gmc jimmy 4x4 sierra classic. '84 k-5 gmc jimmy sierra. '70 cuda 440 6 pack executive edition shaker hood, steering column shift.
     
  3. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    You have TBI small block at 13mpg... is that it? I was getting 14mpg with 33's and 4.56's with a stock 350. Now I have a 350 roller tbi police car motor but not keeping the tbi portion... I was hoping 12-16mpg...??? is that unrealistic?
    my $.02

    1978 Chevy 3/4 - 14" leafs -dana 44w/4.56's -14 bolt corp w/4.56's on 40x17x16.5 Ground Hawgs on 16.5x12 steel rims-NP205&SMC465
     
  4. wayne

    wayne 3/4 ton status

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    I plan to stick with small blocks. I have messed with a bunch of mouse engines and always had good luck with them.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  5. BorregoK5

    BorregoK5 1/2 ton status

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    Stroke a small block, get the best of both worlds without the weight! I'm getting better fuel mileage now with a stroker than with my 350.

    I started with nothing and I still have most of that left! - <a target="_blank" href=http://www.echobit.com:81/k5/> Pictures</a>
     
  6. wayne

    wayne 3/4 ton status

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    I figured the mpg a little low on both. I can say that I did check milage once in my Jimmy when it was stock and running the interstate through a whole tank of gas and got about 13.5 mpg running between 75 and 80 mph on most of it. I was also taking into consideration no overdrive in which most people will not have with a doubler.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  7. txbartman

    txbartman 1/2 ton status

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    I would say stick with the SBC. If you really just have to have the torque, stroke it. It would probably be cheaper to stroke it than to go BBC. I just don't know if you can go TBI with a 383 stroker.

    Brian
    Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!
     
  8. Boss

    Boss 1/2 ton status Author

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    Yeah, what Tx said. After a lot of researching and talking a lot back and forth with CaptCrunch, I don't think you could use your stock TBI stuff with a 383. I'm planning to go with a 383, but another form of FI somehow. As of now, I'm thinking TPI modified to work with a 383. I think Capt and I (well, mostly Capt), came to the conclusion that TPI would be the cheapest way to go with if you're trying to FI a 383. 350s can be built nicely, but will never have the low-end torque that I want that a 383 can push out.
    Boss

    Pic of my truck Before N' After
    <a target="_blank" href=http://coloradok5.com/gallery/BeforeNAfter>http://coloradok5.com/gallery/BeforeNAfter</a>
     
  9. mpascino

    mpascino 1/2 ton status

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    After thinking about it for a bit, It's easy and not to costly to build a small block that performs up to a stock big block level. Also I've found that my gas mileage is still along the lines of 12-13 MPG all depending on my right foot......

    The jeep eater ......[​IMG]
     
  10. wayne

    wayne 3/4 ton status

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    I read an article on 383 with tbi and it can be done but you will have to modify the tbi. TPI is cool though and would look awsome when you pop the hood.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  11. Boss

    Boss 1/2 ton status Author

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    Yeah, it definately can be done, but a lot needs to be changed, driving up cost. But, still, I don't think the modified motor will ever perform the way it should with TBI though. Well, who knows.
    Boss

    Pic of my truck Before N' After
    <a target="_blank" href=http://coloradok5.com/gallery/BeforeNAfter>http://coloradok5.com/gallery/BeforeNAfter</a>
     
  12. BurbinOR

    BurbinOR 3/4 ton status

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    SBC all the way for cost and gas mileage. TPI is the way to go IMHO (gee, sorry if I am prejudiced about this but I've had BBC's, SBC's with carbs and now SBC w/TPI). To be honest with y'all, I spent $3000 for a fully built 400SBC with TPI, a lot of custom stuff done to it, and it rocks. I can get 15mpg (figured off a GPS, not a speedo that is incorrect) if I try.............problem is it runs so well I hate to drive it with an eye on the vacuum gauge (which I have to monitor my right foot's tendency to push down [​IMG]). So for performance it isn't a 496 monster motor like Shawn's but it pulls like a mild big block. I'd go with a 400, a stroked 400 or a 383 (stroked 350) for the extra uumph..........

    As said, it looks pretty cool when you pop the hood too............[​IMG]

    ONE TON</font color=blue> <font color=green>TPI'd</font color=green><font color=red> BEAST<font color=red>
     
  13. four_by_ken

    four_by_ken 1/2 ton status

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    If you are even thinking about gas mileage... go small blokc. Other wise with the weight of a Blazer I would do the big block.

    Hey wait... I did. :-)

    Ken H.


    '86 K5 in parts
    1-ton 454 44 TSLs
     
  14. k20

    k20 3/4 ton status

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    i wanna know how the heck yall get it sooooooo good. my stock 350 33's 4.10's TH400 get 6-8 everywhere. dangit, oh well, who cares, its fun, even if i do have to have a little thinner wallet. :)
     
  15. txoneway

    txoneway Registered Member

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    who cares about gas milage? thats why we have bigboy toys. justa have fun!!! i gotta suburban, so im lookin for a bbc454 to drop in it. i might have one lined out thats already a hotrod, an the price is good.... the guys strapped for cash so maybe pick up the whole blazer for 1000 or less evengot everything i need for the suburban... 454/400 with the 205 and 410 gears in the rear ends. and the hell with the gas milage... aint no replacement for displacement...

    hell yeah, im drunk! what do ya think, im a stunt driver??
     
  16. DesertDueler

    DesertDueler 1/2 ton status

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    Well I have heard BBCs get better gas milage when towing.

    86Jimmy 4"&35"MTRs,87 burb 4"&33"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     
  17. four_by_ken

    four_by_ken 1/2 ton status

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    You should be better than that... but not a whole lot. Unless you have mega miles.

    I have a 85 burban with a slightly built 454, 4.10 gears and 33s. I get about 8-9 all day, anywhere, and about 7 towing a Jeep and a little less than that with a heavier load.

    Ken H.


    '86 K5 in parts
    1-ton 454 44 TSLs
     
  18. POWERMAD

    POWERMAD 1/2 ton status

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    The BBC vs SBC rages on LOL.
    I have 2 BBC rigs, one is bone stock and the other I have spent quite alot of time and money on.
    And plan on spending alot more $$ on.
    SBC's are alot cheaper to build there is no disputing that, and they can be built quite nicely, I have built several nice performing plants.
    But ther is no going back once ya own one or have owned and built one.
    After driving the 73 around and then jumping in the K5....
    I'll take having the BB any day, who gives a crap about mileage? Once the lift and tires go on it won't be a daily anymore anyway.


    <font color=green> Too bad ignorance isn't painful </font color=green>
     
  19. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Hear, hear!! The man has spoken!! [​IMG]

    Yep, BBC any day!! [​IMG]

    I have owned and driven a few SBC that were built, and nothing compares to the BBC, especially if it's built properly.

    Oh yeah, gas mileage, WHAT gas mileage?!?! [​IMG] [​IMG]



    <font color=red>Only real men drive K30's!!!</font color=red> [​IMG]

    <a target="_blank" href=http://coloradok5.com/gallery/thatK30guy>The K30 Collection</a>
     
  20. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    To answer your question. You don't "need" a Big Block, especially if you have a doubler. In certain situations a Big Block can be nice, but it can also be hard on parts and the wallet (MPG). That being said, I currently have a built Mouse motor that will eat stock and most slightly modified Rat motors. I built it because at the time it is what I had. If I were to do it again I will get a built Rat motor. I justify this as it will be in a fullsize pickup (8ft bed). I will definitely tow and continue to truck pull with it. It was thinking of the GM performance 502 with self contained FI. With a few mods I could have that thing putting out the same HP as this Mouse motor with gobs more of Torque (Big blocks have a tendency to do that...[​IMG]), and I might even get better MPG due to the FI (I run a new Edelbrock carb now and still don't get great MPG).
    In a K5 daily driver, with occasional towing duty, I would go with a good 350-383 small block with the correct gear/tire combo and not worry about it, especially if fuel injected, and definitely if I had a doubler.

    See my rig at <a target="_blank" href=http://coloradok5.com/gallery/Leadfoot> click here </a>
     

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