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  1. #1
    Join Date
    May 2007
    Posts
    384

    Default Engine build help please

    Limited Late model engine build advice needed; 350 SBC steel block/steel heads with flat top pistons, 3.48 crank, 10.5 compression, and 4 Bbl carb. 5.7 or 6 inch rods, and why?

    Thanks in advance.

  2. #2

    Default

    6", because it has less working angle as the crank rotates. Puts less pressure against the cylinder walls by being more straight up and down as it works. Also puts the pin higher in the piston which has benefits. We've run even longer than 6, but it's not as common so the price of pistons goes up considerably and there's not near as many options.

  3. #3
    Join Date
    May 2007
    Posts
    384

    Default

    Thanks Basecircle; rules state 5.7 or 6" rods only.

  4. #4
    Join Date
    Dec 2008
    Location
    thedirtysouth
    Posts
    4,013

    Default

    the 6in rods also increases piston dwell , which benefits higher rpm engines , how ever a 5.7 will create more low rpm torque , i have seen both win races , i prefer the 6in on the chevy,s because most tracks are 3/8ths or longer that we race on. My ford all steel engines are 302 based 355cid with 5.4 rods and 1in CH pistons and they pull like a mule off the corner , but you have to coat the piston skirts well , which i would suggest doing on any piston.

  5. #5
    Join Date
    Jul 2015
    Posts
    266

    Default

    This will be in a low RPM motor, there is a 6500 RPM rule

  6. #6
    Join Date
    Feb 2012
    Posts
    1,102

    Default

    Your going to want it to pull harder . A 5.7 rod will help get some grunt out of it. It will also save you some weight to help it rev quicker. IMO the longer rod only benefits you if your going to turn the rpm up. My rule is below 7000 shorter rod .

  7. #7
    Join Date
    Jan 2010
    Location
    MOULTRIE GA
    Posts
    306

    Default

    Fastford how much do you turn your motor with this set up ?

  8. #8
    Join Date
    Dec 2008
    Location
    thedirtysouth
    Posts
    4,013

    Default

    rarely over 7500, with the correct cam , it will pull good to 7000 , but with flat tappets thats about it for usable power.

  9. #9
    Join Date
    Nov 2007
    Posts
    509

    Default

    Rod length plays a bigger role on engines that are restricted. I know drag racers that believe all the rod does is hook the piston to the crank.I always go with a longer rod because I want a lite piston.

  10. #10
    Join Date
    Dec 2007
    Posts
    643

    Default

    what tracks are runing this?

  11. #11
    Join Date
    May 2007
    Posts
    384

    Default

    USRA Late models in midwest

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