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Thread: Spec Carbureted Engines

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    Senior Member Rookie 64GunPilot's Avatar
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    Spec Carbureted Engines

    6.12 & 6.13 Allows the spec carbureted engines. I don't see any posts with folks using these, or asking about them. What kind of power do they put down and is anyone competitive with these setups? I have more than a few vortec 5.7 laying around from 96-99 chevy trucks, tahoes, ect. Just curious if they could be used as spare engines. Update/Backdate rules should not apply in this instance as the rule states the spec as a 5.7 liter with those specific components. Curious about their power numbers. My first tech question of many.

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    Senior Member Carroll Shelby Supercharged111's Avatar
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    What exactly did that car come with for a motor? I believe Bob Denton over in the Great Lakes region has a 3rd gen running a carb'd setup. Matter of fact we have a guy here who hasn't run in a couple years. His wasn't spec but the Dyno came out good with no cheater curve.
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    Senior Member Rookie 64GunPilot's Avatar
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    Quote Originally Posted by Supercharged111 View Post
    What exactly did that car come with for a motor? I believe Bob Denton over in the Great Lakes region has a 3rd gen running a carb'd setup. Matter of fact we have a guy here who hasn't run in a couple years. His wasn't spec but the Dyno came out good with no cheater curve.
    Plum's car (soon to be my car) is a 305 TPI, L31 heads, 255/307 and 3000lbs without driver. Engine is fresh. I guess those numbers, I may not be as competitive. But Im sure it'll be awhile before my driving is good enough to need 11hp to stay with the pack.

    Its legal for me to use any 350 block for a spec carb engine right? I'd just need stock manifolds instead of shorty headers....I think.

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    Senior Member Carroll Shelby Supercharged111's Avatar
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    255/307 is doing really good for a TPI. They tend to make so much more torque than hp that you end up backing timing off to keep from going over on torque. 255hp is plenty, I think the Jordan-mobile makes about that much and they hang out up front. I'd take it to a Dyno myself first and verify what it makes, maybe play with the timing some and see if there isn't a little more in there.
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    Senior Member Grass-Passer
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    Quote Originally Posted by Supercharged111 View Post
    255/307 is doing really good for a TPI. They tend to make so much more torque than hp that you end up backing timing off to keep from going over on torque. 255hp is plenty, I think the Jordan-mobile makes about that much and they hang out up front. I'd take it to a Dyno myself first and verify what it makes, maybe play with the timing some and see if there isn't a little more in there.
    Since when is playing with the timing legal?

  6. #6
    You can do whatever you want with the timing, just have to specify what it is on the dyno sheet.

    7.6.2 Timing tolerance shall be +/- 1 degree.
    Last edited by BADVENM; 10-27-2018 at 05:07 PM.

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    Senior Member Rookie 64GunPilot's Avatar
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    Going back to original object of the thread....is is legal for me to put a carb'd spec 350 in a 3rd Gen? I've read in other places on this forum through searches, that no 350 is allowed in 3rd gens and I quote "period" but they were talking about 350 TPI and I think those threads were at least 10 years old.

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    Senior Member Carroll Shelby Fbody383's Avatar
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    You'll hear this a lot... look at the rules.

    Section 6.13 in part:
    5.7 liter (350ci)
    1. Holley carburetor 600cfm-4bbl #4776
    2. Edelbrock Performer intake manifold #2101, #2104, #2116, #7116, #7516
    3. GM Camshaft #24502476
    4. GM L31 #12558060 or L30 #12552520/12558059 heads
    5. GM OEM H.E.I. distributor (non-computer controlled)

    And just keep asking questions...
    #39 CMC Camaro
    Orange is Fast!
    CMC-NT01 FTW!

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    Senior Member Site AdminCarroll Shelby michaelmosty's Avatar
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    If you are putting down 255/307 numbers then I would not spend another penny on the motor. The extra 5hp will equate to maybe a tenth of a second and will cost tons of money and time to get.

    If you go the carb route on the 305, Bob Denton ran that motor very successfully in previous years in the Great Lakes region.
    -Michael Mosty
    CMC #11 Mosty Brothers' Racing
    Director - TX Region

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    Senior Member Rookie 64GunPilot's Avatar
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    Quote Originally Posted by michaelmosty View Post
    If you are putting down 255/307 numbers then I would not spend another penny on the motor. The extra 5hp will equate to maybe a tenth of a second and will cost tons of money and time to get.

    If you go the carb route on the 305, Bob Denton ran that motor very successfully in previous years in the Great Lakes region.
    Yea I was thinking more of a fresh spare engine. I've been passed Bob Denton's contact info. But Im sure that money is better spent on tires/brakes.

    Speaking of tires....did the previous rules limit the tires to 255 size RA1s? This car hasnt been raced in a few years, and he has like 16 wheels/tires all 255/40/16. Everyone is now running 275 RR? Probably a question for a separate thread. Regardless, Im sure the 255s will be great for DE.

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